Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/kernel/printk.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * | |
6 | * Modified to make sys_syslog() more flexible: added commands to | |
7 | * return the last 4k of kernel messages, regardless of whether | |
8 | * they've been read or not. Added option to suppress kernel printk's | |
9 | * to the console. Added hook for sending the console messages | |
10 | * elsewhere, in preparation for a serial line console (someday). | |
11 | * Ted Ts'o, 2/11/93. | |
12 | * Modified for sysctl support, 1/8/97, Chris Horn. | |
40dc5651 | 13 | * Fixed SMP synchronization, 08/08/99, Manfred Spraul |
624dffcb | 14 | * manfred@colorfullife.com |
1da177e4 | 15 | * Rewrote bits to get rid of console_lock |
e1f8e874 | 16 | * 01Mar01 Andrew Morton |
1da177e4 LT |
17 | */ |
18 | ||
19 | #include <linux/kernel.h> | |
20 | #include <linux/mm.h> | |
21 | #include <linux/tty.h> | |
22 | #include <linux/tty_driver.h> | |
1da177e4 LT |
23 | #include <linux/console.h> |
24 | #include <linux/init.h> | |
bfe8df3d RD |
25 | #include <linux/jiffies.h> |
26 | #include <linux/nmi.h> | |
1da177e4 | 27 | #include <linux/module.h> |
3b9c0410 | 28 | #include <linux/moduleparam.h> |
1da177e4 | 29 | #include <linux/interrupt.h> /* For in_interrupt() */ |
1da177e4 LT |
30 | #include <linux/delay.h> |
31 | #include <linux/smp.h> | |
32 | #include <linux/security.h> | |
33 | #include <linux/bootmem.h> | |
162a7e75 | 34 | #include <linux/memblock.h> |
1da177e4 | 35 | #include <linux/syscalls.h> |
04d491ab | 36 | #include <linux/kexec.h> |
d37d39ae | 37 | #include <linux/kdb.h> |
3fff4c42 | 38 | #include <linux/ratelimit.h> |
456b565c | 39 | #include <linux/kmsg_dump.h> |
00234592 | 40 | #include <linux/syslog.h> |
034260d6 KC |
41 | #include <linux/cpu.h> |
42 | #include <linux/notifier.h> | |
fb842b00 | 43 | #include <linux/rculist.h> |
e11fea92 | 44 | #include <linux/poll.h> |
74876a98 | 45 | #include <linux/irq_work.h> |
196779b9 | 46 | #include <linux/utsname.h> |
249771b8 | 47 | #include <linux/ctype.h> |
e2e40f2c | 48 | #include <linux/uio.h> |
1da177e4 LT |
49 | |
50 | #include <asm/uaccess.h> | |
81cc26f2 | 51 | #include <asm-generic/sections.h> |
1da177e4 | 52 | |
95100358 JB |
53 | #define CREATE_TRACE_POINTS |
54 | #include <trace/events/printk.h> | |
55 | ||
d197c43d | 56 | #include "console_cmdline.h" |
bbeddf52 | 57 | #include "braille.h" |
42a0bb3f | 58 | #include "internal.h" |
d197c43d | 59 | |
1da177e4 | 60 | int console_printk[4] = { |
a8fe19eb | 61 | CONSOLE_LOGLEVEL_DEFAULT, /* console_loglevel */ |
42a9dc0b | 62 | MESSAGE_LOGLEVEL_DEFAULT, /* default_message_loglevel */ |
a8fe19eb BP |
63 | CONSOLE_LOGLEVEL_MIN, /* minimum_console_loglevel */ |
64 | CONSOLE_LOGLEVEL_DEFAULT, /* default_console_loglevel */ | |
1da177e4 LT |
65 | }; |
66 | ||
1da177e4 | 67 | /* |
0bbfb7c2 | 68 | * Low level drivers may need that to know if they can schedule in |
1da177e4 LT |
69 | * their unblank() callback or not. So let's export it. |
70 | */ | |
71 | int oops_in_progress; | |
72 | EXPORT_SYMBOL(oops_in_progress); | |
73 | ||
74 | /* | |
75 | * console_sem protects the console_drivers list, and also | |
76 | * provides serialisation for access to the entire console | |
77 | * driver system. | |
78 | */ | |
5b8c4f23 | 79 | static DEFINE_SEMAPHORE(console_sem); |
1da177e4 | 80 | struct console *console_drivers; |
a29d1cfe IM |
81 | EXPORT_SYMBOL_GPL(console_drivers); |
82 | ||
daee7797 DV |
83 | #ifdef CONFIG_LOCKDEP |
84 | static struct lockdep_map console_lock_dep_map = { | |
85 | .name = "console_lock" | |
86 | }; | |
87 | #endif | |
88 | ||
6fe29354 TH |
89 | /* |
90 | * Number of registered extended console drivers. | |
91 | * | |
92 | * If extended consoles are present, in-kernel cont reassembly is disabled | |
93 | * and each fragment is stored as a separate log entry with proper | |
94 | * continuation flag so that every emitted message has full metadata. This | |
95 | * doesn't change the result for regular consoles or /proc/kmsg. For | |
96 | * /dev/kmsg, as long as the reader concatenates messages according to | |
97 | * consecutive continuation flags, the end result should be the same too. | |
98 | */ | |
99 | static int nr_ext_console_drivers; | |
100 | ||
bd8d7cf5 JK |
101 | /* |
102 | * Helper macros to handle lockdep when locking/unlocking console_sem. We use | |
103 | * macros instead of functions so that _RET_IP_ contains useful information. | |
104 | */ | |
105 | #define down_console_sem() do { \ | |
106 | down(&console_sem);\ | |
107 | mutex_acquire(&console_lock_dep_map, 0, 0, _RET_IP_);\ | |
108 | } while (0) | |
109 | ||
110 | static int __down_trylock_console_sem(unsigned long ip) | |
111 | { | |
112 | if (down_trylock(&console_sem)) | |
113 | return 1; | |
114 | mutex_acquire(&console_lock_dep_map, 0, 1, ip); | |
115 | return 0; | |
116 | } | |
117 | #define down_trylock_console_sem() __down_trylock_console_sem(_RET_IP_) | |
118 | ||
119 | #define up_console_sem() do { \ | |
120 | mutex_release(&console_lock_dep_map, 1, _RET_IP_);\ | |
121 | up(&console_sem);\ | |
122 | } while (0) | |
123 | ||
1da177e4 LT |
124 | /* |
125 | * This is used for debugging the mess that is the VT code by | |
126 | * keeping track if we have the console semaphore held. It's | |
127 | * definitely not the perfect debug tool (we don't know if _WE_ | |
0b90fec3 AE |
128 | * hold it and are racing, but it helps tracking those weird code |
129 | * paths in the console code where we end up in places I want | |
130 | * locked without the console sempahore held). | |
1da177e4 | 131 | */ |
557240b4 | 132 | static int console_locked, console_suspended; |
1da177e4 | 133 | |
fe3d8ad3 FT |
134 | /* |
135 | * If exclusive_console is non-NULL then only this console is to be printed to. | |
136 | */ | |
137 | static struct console *exclusive_console; | |
138 | ||
1da177e4 LT |
139 | /* |
140 | * Array of consoles built from command line options (console=) | |
141 | */ | |
1da177e4 LT |
142 | |
143 | #define MAX_CMDLINECONSOLES 8 | |
144 | ||
145 | static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES]; | |
d197c43d | 146 | |
1da177e4 LT |
147 | static int selected_console = -1; |
148 | static int preferred_console = -1; | |
9e124fe1 MA |
149 | int console_set_on_cmdline; |
150 | EXPORT_SYMBOL(console_set_on_cmdline); | |
1da177e4 LT |
151 | |
152 | /* Flag: console code may call schedule() */ | |
153 | static int console_may_schedule; | |
154 | ||
7ff9554b KS |
155 | /* |
156 | * The printk log buffer consists of a chain of concatenated variable | |
157 | * length records. Every record starts with a record header, containing | |
158 | * the overall length of the record. | |
159 | * | |
160 | * The heads to the first and last entry in the buffer, as well as the | |
0b90fec3 AE |
161 | * sequence numbers of these entries are maintained when messages are |
162 | * stored. | |
7ff9554b KS |
163 | * |
164 | * If the heads indicate available messages, the length in the header | |
165 | * tells the start next message. A length == 0 for the next message | |
166 | * indicates a wrap-around to the beginning of the buffer. | |
167 | * | |
168 | * Every record carries the monotonic timestamp in microseconds, as well as | |
169 | * the standard userspace syslog level and syslog facility. The usual | |
170 | * kernel messages use LOG_KERN; userspace-injected messages always carry | |
171 | * a matching syslog facility, by default LOG_USER. The origin of every | |
172 | * message can be reliably determined that way. | |
173 | * | |
174 | * The human readable log message directly follows the message header. The | |
175 | * length of the message text is stored in the header, the stored message | |
176 | * is not terminated. | |
177 | * | |
e11fea92 KS |
178 | * Optionally, a message can carry a dictionary of properties (key/value pairs), |
179 | * to provide userspace with a machine-readable message context. | |
180 | * | |
181 | * Examples for well-defined, commonly used property names are: | |
182 | * DEVICE=b12:8 device identifier | |
183 | * b12:8 block dev_t | |
184 | * c127:3 char dev_t | |
185 | * n8 netdev ifindex | |
186 | * +sound:card0 subsystem:devname | |
187 | * SUBSYSTEM=pci driver-core subsystem name | |
188 | * | |
189 | * Valid characters in property names are [a-zA-Z0-9.-_]. The plain text value | |
190 | * follows directly after a '=' character. Every property is terminated by | |
191 | * a '\0' character. The last property is not terminated. | |
192 | * | |
193 | * Example of a message structure: | |
194 | * 0000 ff 8f 00 00 00 00 00 00 monotonic time in nsec | |
195 | * 0008 34 00 record is 52 bytes long | |
196 | * 000a 0b 00 text is 11 bytes long | |
197 | * 000c 1f 00 dictionary is 23 bytes long | |
198 | * 000e 03 00 LOG_KERN (facility) LOG_ERR (level) | |
199 | * 0010 69 74 27 73 20 61 20 6c "it's a l" | |
200 | * 69 6e 65 "ine" | |
201 | * 001b 44 45 56 49 43 "DEVIC" | |
202 | * 45 3d 62 38 3a 32 00 44 "E=b8:2\0D" | |
203 | * 52 49 56 45 52 3d 62 75 "RIVER=bu" | |
204 | * 67 "g" | |
205 | * 0032 00 00 00 padding to next message header | |
206 | * | |
62e32ac3 | 207 | * The 'struct printk_log' buffer header must never be directly exported to |
e11fea92 KS |
208 | * userspace, it is a kernel-private implementation detail that might |
209 | * need to be changed in the future, when the requirements change. | |
210 | * | |
211 | * /dev/kmsg exports the structured data in the following line format: | |
b389645f AO |
212 | * "<level>,<sequnum>,<timestamp>,<contflag>[,additional_values, ... ];<message text>\n" |
213 | * | |
214 | * Users of the export format should ignore possible additional values | |
215 | * separated by ',', and find the message after the ';' character. | |
e11fea92 KS |
216 | * |
217 | * The optional key/value pairs are attached as continuation lines starting | |
218 | * with a space character and terminated by a newline. All possible | |
219 | * non-prinatable characters are escaped in the "\xff" notation. | |
7ff9554b KS |
220 | */ |
221 | ||
084681d1 | 222 | enum log_flags { |
5becfb1d KS |
223 | LOG_NOCONS = 1, /* already flushed, do not print to console */ |
224 | LOG_NEWLINE = 2, /* text ended with a newline */ | |
225 | LOG_PREFIX = 4, /* text started with a prefix */ | |
226 | LOG_CONT = 8, /* text is a fragment of a continuation line */ | |
084681d1 KS |
227 | }; |
228 | ||
62e32ac3 | 229 | struct printk_log { |
7ff9554b KS |
230 | u64 ts_nsec; /* timestamp in nanoseconds */ |
231 | u16 len; /* length of entire record */ | |
232 | u16 text_len; /* length of text buffer */ | |
233 | u16 dict_len; /* length of dictionary buffer */ | |
084681d1 KS |
234 | u8 facility; /* syslog facility */ |
235 | u8 flags:5; /* internal record flags */ | |
236 | u8 level:3; /* syslog level */ | |
5c9cf8af AR |
237 | } |
238 | #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS | |
239 | __packed __aligned(4) | |
240 | #endif | |
241 | ; | |
7ff9554b KS |
242 | |
243 | /* | |
458df9fd SR |
244 | * The logbuf_lock protects kmsg buffer, indices, counters. This can be taken |
245 | * within the scheduler's rq lock. It must be released before calling | |
246 | * console_unlock() or anything else that might wake up a process. | |
7ff9554b | 247 | */ |
cf9b1106 | 248 | DEFINE_RAW_SPINLOCK(logbuf_lock); |
d59745ce | 249 | |
96efedf1 | 250 | #ifdef CONFIG_PRINTK |
dc72c32e | 251 | DECLARE_WAIT_QUEUE_HEAD(log_wait); |
7f3a781d KS |
252 | /* the next printk record to read by syslog(READ) or /proc/kmsg */ |
253 | static u64 syslog_seq; | |
254 | static u32 syslog_idx; | |
5becfb1d | 255 | static enum log_flags syslog_prev; |
eb02dac9 | 256 | static size_t syslog_partial; |
7ff9554b KS |
257 | |
258 | /* index and sequence number of the first record stored in the buffer */ | |
259 | static u64 log_first_seq; | |
260 | static u32 log_first_idx; | |
261 | ||
262 | /* index and sequence number of the next record to store in the buffer */ | |
263 | static u64 log_next_seq; | |
264 | static u32 log_next_idx; | |
265 | ||
eab07260 KS |
266 | /* the next printk record to write to the console */ |
267 | static u64 console_seq; | |
268 | static u32 console_idx; | |
269 | static enum log_flags console_prev; | |
270 | ||
7ff9554b KS |
271 | /* the next printk record to read after the last 'clear' command */ |
272 | static u64 clear_seq; | |
273 | static u32 clear_idx; | |
274 | ||
70498253 | 275 | #define PREFIX_MAX 32 |
249771b8 | 276 | #define LOG_LINE_MAX (1024 - PREFIX_MAX) |
7f3a781d | 277 | |
3824657c MK |
278 | #define LOG_LEVEL(v) ((v) & 0x07) |
279 | #define LOG_FACILITY(v) ((v) >> 3 & 0xff) | |
280 | ||
7f3a781d | 281 | /* record buffer */ |
62e32ac3 | 282 | #define LOG_ALIGN __alignof__(struct printk_log) |
7f3a781d | 283 | #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT) |
f8450fca | 284 | static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN); |
7f3a781d KS |
285 | static char *log_buf = __log_buf; |
286 | static u32 log_buf_len = __LOG_BUF_LEN; | |
287 | ||
14c4000a VH |
288 | /* Return log buffer address */ |
289 | char *log_buf_addr_get(void) | |
290 | { | |
291 | return log_buf; | |
292 | } | |
293 | ||
294 | /* Return log buffer size */ | |
295 | u32 log_buf_len_get(void) | |
296 | { | |
297 | return log_buf_len; | |
298 | } | |
299 | ||
7ff9554b | 300 | /* human readable text of the record */ |
62e32ac3 | 301 | static char *log_text(const struct printk_log *msg) |
7ff9554b | 302 | { |
62e32ac3 | 303 | return (char *)msg + sizeof(struct printk_log); |
7ff9554b KS |
304 | } |
305 | ||
306 | /* optional key/value pair dictionary attached to the record */ | |
62e32ac3 | 307 | static char *log_dict(const struct printk_log *msg) |
7ff9554b | 308 | { |
62e32ac3 | 309 | return (char *)msg + sizeof(struct printk_log) + msg->text_len; |
7ff9554b KS |
310 | } |
311 | ||
312 | /* get record by index; idx must point to valid msg */ | |
62e32ac3 | 313 | static struct printk_log *log_from_idx(u32 idx) |
7ff9554b | 314 | { |
62e32ac3 | 315 | struct printk_log *msg = (struct printk_log *)(log_buf + idx); |
7ff9554b KS |
316 | |
317 | /* | |
318 | * A length == 0 record is the end of buffer marker. Wrap around and | |
319 | * read the message at the start of the buffer. | |
320 | */ | |
321 | if (!msg->len) | |
62e32ac3 | 322 | return (struct printk_log *)log_buf; |
7ff9554b KS |
323 | return msg; |
324 | } | |
325 | ||
326 | /* get next record; idx must point to valid msg */ | |
327 | static u32 log_next(u32 idx) | |
328 | { | |
62e32ac3 | 329 | struct printk_log *msg = (struct printk_log *)(log_buf + idx); |
7ff9554b KS |
330 | |
331 | /* length == 0 indicates the end of the buffer; wrap */ | |
332 | /* | |
333 | * A length == 0 record is the end of buffer marker. Wrap around and | |
334 | * read the message at the start of the buffer as *this* one, and | |
335 | * return the one after that. | |
336 | */ | |
337 | if (!msg->len) { | |
62e32ac3 | 338 | msg = (struct printk_log *)log_buf; |
7ff9554b KS |
339 | return msg->len; |
340 | } | |
341 | return idx + msg->len; | |
342 | } | |
343 | ||
f40e4b9f PM |
344 | /* |
345 | * Check whether there is enough free space for the given message. | |
346 | * | |
347 | * The same values of first_idx and next_idx mean that the buffer | |
348 | * is either empty or full. | |
349 | * | |
350 | * If the buffer is empty, we must respect the position of the indexes. | |
351 | * They cannot be reset to the beginning of the buffer. | |
352 | */ | |
353 | static int logbuf_has_space(u32 msg_size, bool empty) | |
0a581694 PM |
354 | { |
355 | u32 free; | |
356 | ||
f40e4b9f | 357 | if (log_next_idx > log_first_idx || empty) |
0a581694 PM |
358 | free = max(log_buf_len - log_next_idx, log_first_idx); |
359 | else | |
360 | free = log_first_idx - log_next_idx; | |
361 | ||
362 | /* | |
363 | * We need space also for an empty header that signalizes wrapping | |
364 | * of the buffer. | |
365 | */ | |
366 | return free >= msg_size + sizeof(struct printk_log); | |
367 | } | |
368 | ||
f40e4b9f | 369 | static int log_make_free_space(u32 msg_size) |
0a581694 | 370 | { |
f468908b ID |
371 | while (log_first_seq < log_next_seq && |
372 | !logbuf_has_space(msg_size, false)) { | |
0b90fec3 | 373 | /* drop old messages until we have enough contiguous space */ |
0a581694 PM |
374 | log_first_idx = log_next(log_first_idx); |
375 | log_first_seq++; | |
376 | } | |
f40e4b9f | 377 | |
f468908b ID |
378 | if (clear_seq < log_first_seq) { |
379 | clear_seq = log_first_seq; | |
380 | clear_idx = log_first_idx; | |
381 | } | |
382 | ||
f40e4b9f | 383 | /* sequence numbers are equal, so the log buffer is empty */ |
f468908b | 384 | if (logbuf_has_space(msg_size, log_first_seq == log_next_seq)) |
f40e4b9f PM |
385 | return 0; |
386 | ||
387 | return -ENOMEM; | |
0a581694 PM |
388 | } |
389 | ||
85c87043 PM |
390 | /* compute the message size including the padding bytes */ |
391 | static u32 msg_used_size(u16 text_len, u16 dict_len, u32 *pad_len) | |
392 | { | |
393 | u32 size; | |
394 | ||
395 | size = sizeof(struct printk_log) + text_len + dict_len; | |
396 | *pad_len = (-size) & (LOG_ALIGN - 1); | |
397 | size += *pad_len; | |
398 | ||
399 | return size; | |
400 | } | |
401 | ||
55bd53a4 PM |
402 | /* |
403 | * Define how much of the log buffer we could take at maximum. The value | |
404 | * must be greater than two. Note that only half of the buffer is available | |
405 | * when the index points to the middle. | |
406 | */ | |
407 | #define MAX_LOG_TAKE_PART 4 | |
408 | static const char trunc_msg[] = "<truncated>"; | |
409 | ||
410 | static u32 truncate_msg(u16 *text_len, u16 *trunc_msg_len, | |
411 | u16 *dict_len, u32 *pad_len) | |
412 | { | |
413 | /* | |
414 | * The message should not take the whole buffer. Otherwise, it might | |
415 | * get removed too soon. | |
416 | */ | |
417 | u32 max_text_len = log_buf_len / MAX_LOG_TAKE_PART; | |
418 | if (*text_len > max_text_len) | |
419 | *text_len = max_text_len; | |
420 | /* enable the warning message */ | |
421 | *trunc_msg_len = strlen(trunc_msg); | |
422 | /* disable the "dict" completely */ | |
423 | *dict_len = 0; | |
424 | /* compute the size again, count also the warning message */ | |
425 | return msg_used_size(*text_len + *trunc_msg_len, 0, pad_len); | |
426 | } | |
427 | ||
7ff9554b | 428 | /* insert record into the buffer, discard old ones, update heads */ |
034633cc PM |
429 | static int log_store(int facility, int level, |
430 | enum log_flags flags, u64 ts_nsec, | |
431 | const char *dict, u16 dict_len, | |
432 | const char *text, u16 text_len) | |
7ff9554b | 433 | { |
62e32ac3 | 434 | struct printk_log *msg; |
7ff9554b | 435 | u32 size, pad_len; |
55bd53a4 | 436 | u16 trunc_msg_len = 0; |
7ff9554b KS |
437 | |
438 | /* number of '\0' padding bytes to next message */ | |
85c87043 | 439 | size = msg_used_size(text_len, dict_len, &pad_len); |
7ff9554b | 440 | |
55bd53a4 PM |
441 | if (log_make_free_space(size)) { |
442 | /* truncate the message if it is too long for empty buffer */ | |
443 | size = truncate_msg(&text_len, &trunc_msg_len, | |
444 | &dict_len, &pad_len); | |
445 | /* survive when the log buffer is too small for trunc_msg */ | |
446 | if (log_make_free_space(size)) | |
034633cc | 447 | return 0; |
55bd53a4 | 448 | } |
7ff9554b | 449 | |
39b25109 | 450 | if (log_next_idx + size + sizeof(struct printk_log) > log_buf_len) { |
7ff9554b KS |
451 | /* |
452 | * This message + an additional empty header does not fit | |
453 | * at the end of the buffer. Add an empty header with len == 0 | |
454 | * to signify a wrap around. | |
455 | */ | |
62e32ac3 | 456 | memset(log_buf + log_next_idx, 0, sizeof(struct printk_log)); |
7ff9554b KS |
457 | log_next_idx = 0; |
458 | } | |
459 | ||
460 | /* fill message */ | |
62e32ac3 | 461 | msg = (struct printk_log *)(log_buf + log_next_idx); |
7ff9554b KS |
462 | memcpy(log_text(msg), text, text_len); |
463 | msg->text_len = text_len; | |
55bd53a4 PM |
464 | if (trunc_msg_len) { |
465 | memcpy(log_text(msg) + text_len, trunc_msg, trunc_msg_len); | |
466 | msg->text_len += trunc_msg_len; | |
467 | } | |
7ff9554b KS |
468 | memcpy(log_dict(msg), dict, dict_len); |
469 | msg->dict_len = dict_len; | |
084681d1 KS |
470 | msg->facility = facility; |
471 | msg->level = level & 7; | |
472 | msg->flags = flags & 0x1f; | |
473 | if (ts_nsec > 0) | |
474 | msg->ts_nsec = ts_nsec; | |
475 | else | |
476 | msg->ts_nsec = local_clock(); | |
7ff9554b | 477 | memset(log_dict(msg) + dict_len, 0, pad_len); |
fce6e033 | 478 | msg->len = size; |
7ff9554b KS |
479 | |
480 | /* insert message */ | |
481 | log_next_idx += msg->len; | |
482 | log_next_seq++; | |
034633cc PM |
483 | |
484 | return msg->text_len; | |
7ff9554b | 485 | } |
d59745ce | 486 | |
e99aa461 | 487 | int dmesg_restrict = IS_ENABLED(CONFIG_SECURITY_DMESG_RESTRICT); |
637241a9 KC |
488 | |
489 | static int syslog_action_restricted(int type) | |
490 | { | |
491 | if (dmesg_restrict) | |
492 | return 1; | |
493 | /* | |
494 | * Unless restricted, we allow "read all" and "get buffer size" | |
495 | * for everybody. | |
496 | */ | |
497 | return type != SYSLOG_ACTION_READ_ALL && | |
498 | type != SYSLOG_ACTION_SIZE_BUFFER; | |
499 | } | |
500 | ||
3ea4331c | 501 | int check_syslog_permissions(int type, int source) |
637241a9 KC |
502 | { |
503 | /* | |
504 | * If this is from /proc/kmsg and we've already opened it, then we've | |
505 | * already done the capabilities checks at open time. | |
506 | */ | |
3ea4331c | 507 | if (source == SYSLOG_FROM_PROC && type != SYSLOG_ACTION_OPEN) |
d194e5d6 | 508 | goto ok; |
637241a9 KC |
509 | |
510 | if (syslog_action_restricted(type)) { | |
511 | if (capable(CAP_SYSLOG)) | |
d194e5d6 | 512 | goto ok; |
637241a9 KC |
513 | /* |
514 | * For historical reasons, accept CAP_SYS_ADMIN too, with | |
515 | * a warning. | |
516 | */ | |
517 | if (capable(CAP_SYS_ADMIN)) { | |
518 | pr_warn_once("%s (%d): Attempt to access syslog with " | |
519 | "CAP_SYS_ADMIN but no CAP_SYSLOG " | |
520 | "(deprecated).\n", | |
521 | current->comm, task_pid_nr(current)); | |
d194e5d6 | 522 | goto ok; |
637241a9 KC |
523 | } |
524 | return -EPERM; | |
525 | } | |
d194e5d6 | 526 | ok: |
637241a9 KC |
527 | return security_syslog(type); |
528 | } | |
ee1d2674 | 529 | EXPORT_SYMBOL_GPL(check_syslog_permissions); |
637241a9 | 530 | |
d43ff430 TH |
531 | static void append_char(char **pp, char *e, char c) |
532 | { | |
533 | if (*pp < e) | |
534 | *(*pp)++ = c; | |
535 | } | |
637241a9 | 536 | |
0a295e67 TH |
537 | static ssize_t msg_print_ext_header(char *buf, size_t size, |
538 | struct printk_log *msg, u64 seq, | |
539 | enum log_flags prev_flags) | |
540 | { | |
541 | u64 ts_usec = msg->ts_nsec; | |
542 | char cont = '-'; | |
543 | ||
544 | do_div(ts_usec, 1000); | |
545 | ||
546 | /* | |
547 | * If we couldn't merge continuation line fragments during the print, | |
548 | * export the stored flags to allow an optional external merge of the | |
549 | * records. Merging the records isn't always neccessarily correct, like | |
550 | * when we hit a race during printing. In most cases though, it produces | |
551 | * better readable output. 'c' in the record flags mark the first | |
552 | * fragment of a line, '+' the following. | |
553 | */ | |
554 | if (msg->flags & LOG_CONT && !(prev_flags & LOG_CONT)) | |
555 | cont = 'c'; | |
556 | else if ((msg->flags & LOG_CONT) || | |
557 | ((prev_flags & LOG_CONT) && !(msg->flags & LOG_PREFIX))) | |
558 | cont = '+'; | |
559 | ||
560 | return scnprintf(buf, size, "%u,%llu,%llu,%c;", | |
561 | (msg->facility << 3) | msg->level, seq, ts_usec, cont); | |
562 | } | |
563 | ||
564 | static ssize_t msg_print_ext_body(char *buf, size_t size, | |
565 | char *dict, size_t dict_len, | |
566 | char *text, size_t text_len) | |
567 | { | |
568 | char *p = buf, *e = buf + size; | |
569 | size_t i; | |
570 | ||
571 | /* escape non-printable characters */ | |
572 | for (i = 0; i < text_len; i++) { | |
573 | unsigned char c = text[i]; | |
574 | ||
575 | if (c < ' ' || c >= 127 || c == '\\') | |
576 | p += scnprintf(p, e - p, "\\x%02x", c); | |
577 | else | |
578 | append_char(&p, e, c); | |
579 | } | |
580 | append_char(&p, e, '\n'); | |
581 | ||
582 | if (dict_len) { | |
583 | bool line = true; | |
584 | ||
585 | for (i = 0; i < dict_len; i++) { | |
586 | unsigned char c = dict[i]; | |
587 | ||
588 | if (line) { | |
589 | append_char(&p, e, ' '); | |
590 | line = false; | |
591 | } | |
592 | ||
593 | if (c == '\0') { | |
594 | append_char(&p, e, '\n'); | |
595 | line = true; | |
596 | continue; | |
597 | } | |
598 | ||
599 | if (c < ' ' || c >= 127 || c == '\\') { | |
600 | p += scnprintf(p, e - p, "\\x%02x", c); | |
601 | continue; | |
602 | } | |
603 | ||
604 | append_char(&p, e, c); | |
605 | } | |
606 | append_char(&p, e, '\n'); | |
607 | } | |
608 | ||
609 | return p - buf; | |
610 | } | |
611 | ||
e11fea92 KS |
612 | /* /dev/kmsg - userspace message inject/listen interface */ |
613 | struct devkmsg_user { | |
614 | u64 seq; | |
615 | u32 idx; | |
d39f3d77 | 616 | enum log_flags prev; |
e11fea92 | 617 | struct mutex lock; |
d43ff430 | 618 | char buf[CONSOLE_EXT_LOG_MAX]; |
e11fea92 KS |
619 | }; |
620 | ||
849f3127 | 621 | static ssize_t devkmsg_write(struct kiocb *iocb, struct iov_iter *from) |
e11fea92 KS |
622 | { |
623 | char *buf, *line; | |
e11fea92 KS |
624 | int level = default_message_loglevel; |
625 | int facility = 1; /* LOG_USER */ | |
66ee59af | 626 | size_t len = iov_iter_count(from); |
e11fea92 KS |
627 | ssize_t ret = len; |
628 | ||
629 | if (len > LOG_LINE_MAX) | |
630 | return -EINVAL; | |
631 | buf = kmalloc(len+1, GFP_KERNEL); | |
632 | if (buf == NULL) | |
633 | return -ENOMEM; | |
634 | ||
849f3127 AV |
635 | buf[len] = '\0'; |
636 | if (copy_from_iter(buf, len, from) != len) { | |
637 | kfree(buf); | |
638 | return -EFAULT; | |
e11fea92 KS |
639 | } |
640 | ||
641 | /* | |
642 | * Extract and skip the syslog prefix <[0-9]*>. Coming from userspace | |
643 | * the decimal value represents 32bit, the lower 3 bit are the log | |
644 | * level, the rest are the log facility. | |
645 | * | |
646 | * If no prefix or no userspace facility is specified, we | |
647 | * enforce LOG_USER, to be able to reliably distinguish | |
648 | * kernel-generated messages from userspace-injected ones. | |
649 | */ | |
650 | line = buf; | |
651 | if (line[0] == '<') { | |
652 | char *endp = NULL; | |
3824657c | 653 | unsigned int u; |
e11fea92 | 654 | |
3824657c | 655 | u = simple_strtoul(line + 1, &endp, 10); |
e11fea92 | 656 | if (endp && endp[0] == '>') { |
3824657c MK |
657 | level = LOG_LEVEL(u); |
658 | if (LOG_FACILITY(u) != 0) | |
659 | facility = LOG_FACILITY(u); | |
e11fea92 KS |
660 | endp++; |
661 | len -= endp - line; | |
662 | line = endp; | |
663 | } | |
664 | } | |
e11fea92 KS |
665 | |
666 | printk_emit(facility, level, NULL, 0, "%s", line); | |
e11fea92 KS |
667 | kfree(buf); |
668 | return ret; | |
669 | } | |
670 | ||
671 | static ssize_t devkmsg_read(struct file *file, char __user *buf, | |
672 | size_t count, loff_t *ppos) | |
673 | { | |
674 | struct devkmsg_user *user = file->private_data; | |
62e32ac3 | 675 | struct printk_log *msg; |
e11fea92 KS |
676 | size_t len; |
677 | ssize_t ret; | |
678 | ||
679 | if (!user) | |
680 | return -EBADF; | |
681 | ||
4a77a5a0 YL |
682 | ret = mutex_lock_interruptible(&user->lock); |
683 | if (ret) | |
684 | return ret; | |
5c53d819 | 685 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
686 | while (user->seq == log_next_seq) { |
687 | if (file->f_flags & O_NONBLOCK) { | |
688 | ret = -EAGAIN; | |
5c53d819 | 689 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
690 | goto out; |
691 | } | |
692 | ||
5c53d819 | 693 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
694 | ret = wait_event_interruptible(log_wait, |
695 | user->seq != log_next_seq); | |
696 | if (ret) | |
697 | goto out; | |
5c53d819 | 698 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
699 | } |
700 | ||
701 | if (user->seq < log_first_seq) { | |
702 | /* our last seen message is gone, return error and reset */ | |
703 | user->idx = log_first_idx; | |
704 | user->seq = log_first_seq; | |
705 | ret = -EPIPE; | |
5c53d819 | 706 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
707 | goto out; |
708 | } | |
709 | ||
710 | msg = log_from_idx(user->idx); | |
0a295e67 TH |
711 | len = msg_print_ext_header(user->buf, sizeof(user->buf), |
712 | msg, user->seq, user->prev); | |
713 | len += msg_print_ext_body(user->buf + len, sizeof(user->buf) - len, | |
714 | log_dict(msg), msg->dict_len, | |
715 | log_text(msg), msg->text_len); | |
d39f3d77 | 716 | |
d39f3d77 | 717 | user->prev = msg->flags; |
e11fea92 KS |
718 | user->idx = log_next(user->idx); |
719 | user->seq++; | |
5c53d819 | 720 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
721 | |
722 | if (len > count) { | |
723 | ret = -EINVAL; | |
724 | goto out; | |
725 | } | |
726 | ||
727 | if (copy_to_user(buf, user->buf, len)) { | |
728 | ret = -EFAULT; | |
729 | goto out; | |
730 | } | |
731 | ret = len; | |
732 | out: | |
733 | mutex_unlock(&user->lock); | |
734 | return ret; | |
735 | } | |
736 | ||
737 | static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence) | |
738 | { | |
739 | struct devkmsg_user *user = file->private_data; | |
740 | loff_t ret = 0; | |
741 | ||
742 | if (!user) | |
743 | return -EBADF; | |
744 | if (offset) | |
745 | return -ESPIPE; | |
746 | ||
5c53d819 | 747 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
748 | switch (whence) { |
749 | case SEEK_SET: | |
750 | /* the first record */ | |
751 | user->idx = log_first_idx; | |
752 | user->seq = log_first_seq; | |
753 | break; | |
754 | case SEEK_DATA: | |
755 | /* | |
756 | * The first record after the last SYSLOG_ACTION_CLEAR, | |
757 | * like issued by 'dmesg -c'. Reading /dev/kmsg itself | |
758 | * changes no global state, and does not clear anything. | |
759 | */ | |
760 | user->idx = clear_idx; | |
761 | user->seq = clear_seq; | |
762 | break; | |
763 | case SEEK_END: | |
764 | /* after the last record */ | |
765 | user->idx = log_next_idx; | |
766 | user->seq = log_next_seq; | |
767 | break; | |
768 | default: | |
769 | ret = -EINVAL; | |
770 | } | |
5c53d819 | 771 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
772 | return ret; |
773 | } | |
774 | ||
775 | static unsigned int devkmsg_poll(struct file *file, poll_table *wait) | |
776 | { | |
777 | struct devkmsg_user *user = file->private_data; | |
778 | int ret = 0; | |
779 | ||
780 | if (!user) | |
781 | return POLLERR|POLLNVAL; | |
782 | ||
783 | poll_wait(file, &log_wait, wait); | |
784 | ||
5c53d819 | 785 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
786 | if (user->seq < log_next_seq) { |
787 | /* return error when data has vanished underneath us */ | |
788 | if (user->seq < log_first_seq) | |
789 | ret = POLLIN|POLLRDNORM|POLLERR|POLLPRI; | |
0a285317 NK |
790 | else |
791 | ret = POLLIN|POLLRDNORM; | |
e11fea92 | 792 | } |
5c53d819 | 793 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
794 | |
795 | return ret; | |
796 | } | |
797 | ||
798 | static int devkmsg_open(struct inode *inode, struct file *file) | |
799 | { | |
800 | struct devkmsg_user *user; | |
801 | int err; | |
802 | ||
803 | /* write-only does not need any file context */ | |
804 | if ((file->f_flags & O_ACCMODE) == O_WRONLY) | |
805 | return 0; | |
806 | ||
637241a9 KC |
807 | err = check_syslog_permissions(SYSLOG_ACTION_READ_ALL, |
808 | SYSLOG_FROM_READER); | |
e11fea92 KS |
809 | if (err) |
810 | return err; | |
811 | ||
812 | user = kmalloc(sizeof(struct devkmsg_user), GFP_KERNEL); | |
813 | if (!user) | |
814 | return -ENOMEM; | |
815 | ||
816 | mutex_init(&user->lock); | |
817 | ||
5c53d819 | 818 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
819 | user->idx = log_first_idx; |
820 | user->seq = log_first_seq; | |
5c53d819 | 821 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
822 | |
823 | file->private_data = user; | |
824 | return 0; | |
825 | } | |
826 | ||
827 | static int devkmsg_release(struct inode *inode, struct file *file) | |
828 | { | |
829 | struct devkmsg_user *user = file->private_data; | |
830 | ||
831 | if (!user) | |
832 | return 0; | |
833 | ||
834 | mutex_destroy(&user->lock); | |
835 | kfree(user); | |
836 | return 0; | |
837 | } | |
838 | ||
839 | const struct file_operations kmsg_fops = { | |
840 | .open = devkmsg_open, | |
841 | .read = devkmsg_read, | |
849f3127 | 842 | .write_iter = devkmsg_write, |
e11fea92 KS |
843 | .llseek = devkmsg_llseek, |
844 | .poll = devkmsg_poll, | |
845 | .release = devkmsg_release, | |
846 | }; | |
847 | ||
2965faa5 | 848 | #ifdef CONFIG_KEXEC_CORE |
04d491ab | 849 | /* |
4c1ace64 | 850 | * This appends the listed symbols to /proc/vmcore |
04d491ab | 851 | * |
4c1ace64 | 852 | * /proc/vmcore is used by various utilities, like crash and makedumpfile to |
04d491ab NH |
853 | * obtain access to symbols that are otherwise very difficult to locate. These |
854 | * symbols are specifically used so that utilities can access and extract the | |
855 | * dmesg log from a vmcore file after a crash. | |
856 | */ | |
857 | void log_buf_kexec_setup(void) | |
858 | { | |
859 | VMCOREINFO_SYMBOL(log_buf); | |
04d491ab | 860 | VMCOREINFO_SYMBOL(log_buf_len); |
7ff9554b | 861 | VMCOREINFO_SYMBOL(log_first_idx); |
f468908b | 862 | VMCOREINFO_SYMBOL(clear_idx); |
7ff9554b | 863 | VMCOREINFO_SYMBOL(log_next_idx); |
6791457a | 864 | /* |
62e32ac3 | 865 | * Export struct printk_log size and field offsets. User space tools can |
6791457a VG |
866 | * parse it and detect any changes to structure down the line. |
867 | */ | |
62e32ac3 JP |
868 | VMCOREINFO_STRUCT_SIZE(printk_log); |
869 | VMCOREINFO_OFFSET(printk_log, ts_nsec); | |
870 | VMCOREINFO_OFFSET(printk_log, len); | |
871 | VMCOREINFO_OFFSET(printk_log, text_len); | |
872 | VMCOREINFO_OFFSET(printk_log, dict_len); | |
04d491ab NH |
873 | } |
874 | #endif | |
875 | ||
162a7e75 MT |
876 | /* requested log_buf_len from kernel cmdline */ |
877 | static unsigned long __initdata new_log_buf_len; | |
878 | ||
c0a318a3 LR |
879 | /* we practice scaling the ring buffer by powers of 2 */ |
880 | static void __init log_buf_len_update(unsigned size) | |
1da177e4 | 881 | { |
1da177e4 LT |
882 | if (size) |
883 | size = roundup_pow_of_two(size); | |
162a7e75 MT |
884 | if (size > log_buf_len) |
885 | new_log_buf_len = size; | |
c0a318a3 LR |
886 | } |
887 | ||
888 | /* save requested log_buf_len since it's too early to process it */ | |
889 | static int __init log_buf_len_setup(char *str) | |
890 | { | |
891 | unsigned size = memparse(str, &str); | |
892 | ||
893 | log_buf_len_update(size); | |
162a7e75 MT |
894 | |
895 | return 0; | |
1da177e4 | 896 | } |
162a7e75 MT |
897 | early_param("log_buf_len", log_buf_len_setup); |
898 | ||
2240a31d GU |
899 | #ifdef CONFIG_SMP |
900 | #define __LOG_CPU_MAX_BUF_LEN (1 << CONFIG_LOG_CPU_MAX_BUF_SHIFT) | |
901 | ||
23b2899f LR |
902 | static void __init log_buf_add_cpu(void) |
903 | { | |
904 | unsigned int cpu_extra; | |
905 | ||
906 | /* | |
907 | * archs should set up cpu_possible_bits properly with | |
908 | * set_cpu_possible() after setup_arch() but just in | |
909 | * case lets ensure this is valid. | |
910 | */ | |
911 | if (num_possible_cpus() == 1) | |
912 | return; | |
913 | ||
914 | cpu_extra = (num_possible_cpus() - 1) * __LOG_CPU_MAX_BUF_LEN; | |
915 | ||
916 | /* by default this will only continue through for large > 64 CPUs */ | |
917 | if (cpu_extra <= __LOG_BUF_LEN / 2) | |
918 | return; | |
919 | ||
920 | pr_info("log_buf_len individual max cpu contribution: %d bytes\n", | |
921 | __LOG_CPU_MAX_BUF_LEN); | |
922 | pr_info("log_buf_len total cpu_extra contributions: %d bytes\n", | |
923 | cpu_extra); | |
924 | pr_info("log_buf_len min size: %d bytes\n", __LOG_BUF_LEN); | |
925 | ||
926 | log_buf_len_update(cpu_extra + __LOG_BUF_LEN); | |
927 | } | |
2240a31d GU |
928 | #else /* !CONFIG_SMP */ |
929 | static inline void log_buf_add_cpu(void) {} | |
930 | #endif /* CONFIG_SMP */ | |
23b2899f | 931 | |
162a7e75 MT |
932 | void __init setup_log_buf(int early) |
933 | { | |
934 | unsigned long flags; | |
162a7e75 MT |
935 | char *new_log_buf; |
936 | int free; | |
937 | ||
23b2899f LR |
938 | if (log_buf != __log_buf) |
939 | return; | |
940 | ||
941 | if (!early && !new_log_buf_len) | |
942 | log_buf_add_cpu(); | |
943 | ||
162a7e75 MT |
944 | if (!new_log_buf_len) |
945 | return; | |
1da177e4 | 946 | |
162a7e75 | 947 | if (early) { |
9da791df | 948 | new_log_buf = |
70300177 | 949 | memblock_virt_alloc(new_log_buf_len, LOG_ALIGN); |
162a7e75 | 950 | } else { |
70300177 LR |
951 | new_log_buf = memblock_virt_alloc_nopanic(new_log_buf_len, |
952 | LOG_ALIGN); | |
162a7e75 MT |
953 | } |
954 | ||
955 | if (unlikely(!new_log_buf)) { | |
956 | pr_err("log_buf_len: %ld bytes not available\n", | |
957 | new_log_buf_len); | |
958 | return; | |
959 | } | |
960 | ||
07354eb1 | 961 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
162a7e75 MT |
962 | log_buf_len = new_log_buf_len; |
963 | log_buf = new_log_buf; | |
964 | new_log_buf_len = 0; | |
7ff9554b KS |
965 | free = __LOG_BUF_LEN - log_next_idx; |
966 | memcpy(log_buf, __log_buf, __LOG_BUF_LEN); | |
07354eb1 | 967 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
162a7e75 | 968 | |
f5405172 | 969 | pr_info("log_buf_len: %d bytes\n", log_buf_len); |
162a7e75 MT |
970 | pr_info("early log buf free: %d(%d%%)\n", |
971 | free, (free * 100) / __LOG_BUF_LEN); | |
972 | } | |
1da177e4 | 973 | |
2fa72c8f AC |
974 | static bool __read_mostly ignore_loglevel; |
975 | ||
976 | static int __init ignore_loglevel_setup(char *str) | |
977 | { | |
d25d9fec | 978 | ignore_loglevel = true; |
27083bac | 979 | pr_info("debug: ignoring loglevel setting.\n"); |
2fa72c8f AC |
980 | |
981 | return 0; | |
982 | } | |
983 | ||
984 | early_param("ignore_loglevel", ignore_loglevel_setup); | |
985 | module_param(ignore_loglevel, bool, S_IRUGO | S_IWUSR); | |
205bd3d2 JP |
986 | MODULE_PARM_DESC(ignore_loglevel, |
987 | "ignore loglevel setting (prints all kernel messages to the console)"); | |
2fa72c8f | 988 | |
bfe8df3d RD |
989 | #ifdef CONFIG_BOOT_PRINTK_DELAY |
990 | ||
674dff65 | 991 | static int boot_delay; /* msecs delay after each printk during bootup */ |
3a3b6ed2 | 992 | static unsigned long long loops_per_msec; /* based on boot_delay */ |
bfe8df3d RD |
993 | |
994 | static int __init boot_delay_setup(char *str) | |
995 | { | |
996 | unsigned long lpj; | |
bfe8df3d RD |
997 | |
998 | lpj = preset_lpj ? preset_lpj : 1000000; /* some guess */ | |
999 | loops_per_msec = (unsigned long long)lpj / 1000 * HZ; | |
1000 | ||
1001 | get_option(&str, &boot_delay); | |
1002 | if (boot_delay > 10 * 1000) | |
1003 | boot_delay = 0; | |
1004 | ||
3a3b6ed2 DY |
1005 | pr_debug("boot_delay: %u, preset_lpj: %ld, lpj: %lu, " |
1006 | "HZ: %d, loops_per_msec: %llu\n", | |
1007 | boot_delay, preset_lpj, lpj, HZ, loops_per_msec); | |
29e9d225 | 1008 | return 0; |
bfe8df3d | 1009 | } |
29e9d225 | 1010 | early_param("boot_delay", boot_delay_setup); |
bfe8df3d | 1011 | |
2fa72c8f | 1012 | static void boot_delay_msec(int level) |
bfe8df3d RD |
1013 | { |
1014 | unsigned long long k; | |
1015 | unsigned long timeout; | |
1016 | ||
2fa72c8f AC |
1017 | if ((boot_delay == 0 || system_state != SYSTEM_BOOTING) |
1018 | || (level >= console_loglevel && !ignore_loglevel)) { | |
bfe8df3d | 1019 | return; |
2fa72c8f | 1020 | } |
bfe8df3d | 1021 | |
3a3b6ed2 | 1022 | k = (unsigned long long)loops_per_msec * boot_delay; |
bfe8df3d RD |
1023 | |
1024 | timeout = jiffies + msecs_to_jiffies(boot_delay); | |
1025 | while (k) { | |
1026 | k--; | |
1027 | cpu_relax(); | |
1028 | /* | |
1029 | * use (volatile) jiffies to prevent | |
1030 | * compiler reduction; loop termination via jiffies | |
1031 | * is secondary and may or may not happen. | |
1032 | */ | |
1033 | if (time_after(jiffies, timeout)) | |
1034 | break; | |
1035 | touch_nmi_watchdog(); | |
1036 | } | |
1037 | } | |
1038 | #else | |
2fa72c8f | 1039 | static inline void boot_delay_msec(int level) |
bfe8df3d RD |
1040 | { |
1041 | } | |
1042 | #endif | |
1043 | ||
e99aa461 | 1044 | static bool printk_time = IS_ENABLED(CONFIG_PRINTK_TIME); |
7ff9554b KS |
1045 | module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR); |
1046 | ||
084681d1 KS |
1047 | static size_t print_time(u64 ts, char *buf) |
1048 | { | |
1049 | unsigned long rem_nsec; | |
1050 | ||
1051 | if (!printk_time) | |
1052 | return 0; | |
1053 | ||
35dac27c RD |
1054 | rem_nsec = do_div(ts, 1000000000); |
1055 | ||
084681d1 | 1056 | if (!buf) |
35dac27c | 1057 | return snprintf(NULL, 0, "[%5lu.000000] ", (unsigned long)ts); |
084681d1 | 1058 | |
084681d1 KS |
1059 | return sprintf(buf, "[%5lu.%06lu] ", |
1060 | (unsigned long)ts, rem_nsec / 1000); | |
1061 | } | |
1062 | ||
62e32ac3 | 1063 | static size_t print_prefix(const struct printk_log *msg, bool syslog, char *buf) |
649e6ee3 | 1064 | { |
3ce9a7c0 | 1065 | size_t len = 0; |
43a73a50 | 1066 | unsigned int prefix = (msg->facility << 3) | msg->level; |
649e6ee3 | 1067 | |
3ce9a7c0 KS |
1068 | if (syslog) { |
1069 | if (buf) { | |
43a73a50 | 1070 | len += sprintf(buf, "<%u>", prefix); |
3ce9a7c0 KS |
1071 | } else { |
1072 | len += 3; | |
43a73a50 KS |
1073 | if (prefix > 999) |
1074 | len += 3; | |
1075 | else if (prefix > 99) | |
1076 | len += 2; | |
1077 | else if (prefix > 9) | |
3ce9a7c0 KS |
1078 | len++; |
1079 | } | |
1080 | } | |
649e6ee3 | 1081 | |
084681d1 | 1082 | len += print_time(msg->ts_nsec, buf ? buf + len : NULL); |
3ce9a7c0 | 1083 | return len; |
649e6ee3 KS |
1084 | } |
1085 | ||
62e32ac3 | 1086 | static size_t msg_print_text(const struct printk_log *msg, enum log_flags prev, |
5becfb1d | 1087 | bool syslog, char *buf, size_t size) |
7ff9554b | 1088 | { |
3ce9a7c0 KS |
1089 | const char *text = log_text(msg); |
1090 | size_t text_size = msg->text_len; | |
5becfb1d KS |
1091 | bool prefix = true; |
1092 | bool newline = true; | |
3ce9a7c0 KS |
1093 | size_t len = 0; |
1094 | ||
5becfb1d KS |
1095 | if ((prev & LOG_CONT) && !(msg->flags & LOG_PREFIX)) |
1096 | prefix = false; | |
1097 | ||
1098 | if (msg->flags & LOG_CONT) { | |
1099 | if ((prev & LOG_CONT) && !(prev & LOG_NEWLINE)) | |
1100 | prefix = false; | |
1101 | ||
1102 | if (!(msg->flags & LOG_NEWLINE)) | |
1103 | newline = false; | |
1104 | } | |
1105 | ||
3ce9a7c0 KS |
1106 | do { |
1107 | const char *next = memchr(text, '\n', text_size); | |
1108 | size_t text_len; | |
1109 | ||
1110 | if (next) { | |
1111 | text_len = next - text; | |
1112 | next++; | |
1113 | text_size -= next - text; | |
1114 | } else { | |
1115 | text_len = text_size; | |
1116 | } | |
7ff9554b | 1117 | |
3ce9a7c0 KS |
1118 | if (buf) { |
1119 | if (print_prefix(msg, syslog, NULL) + | |
70498253 | 1120 | text_len + 1 >= size - len) |
3ce9a7c0 | 1121 | break; |
7ff9554b | 1122 | |
5becfb1d KS |
1123 | if (prefix) |
1124 | len += print_prefix(msg, syslog, buf + len); | |
3ce9a7c0 KS |
1125 | memcpy(buf + len, text, text_len); |
1126 | len += text_len; | |
5becfb1d KS |
1127 | if (next || newline) |
1128 | buf[len++] = '\n'; | |
3ce9a7c0 KS |
1129 | } else { |
1130 | /* SYSLOG_ACTION_* buffer size only calculation */ | |
5becfb1d KS |
1131 | if (prefix) |
1132 | len += print_prefix(msg, syslog, NULL); | |
1133 | len += text_len; | |
1134 | if (next || newline) | |
1135 | len++; | |
3ce9a7c0 | 1136 | } |
7ff9554b | 1137 | |
5becfb1d | 1138 | prefix = true; |
3ce9a7c0 KS |
1139 | text = next; |
1140 | } while (text); | |
7ff9554b | 1141 | |
7ff9554b KS |
1142 | return len; |
1143 | } | |
1144 | ||
1145 | static int syslog_print(char __user *buf, int size) | |
1146 | { | |
1147 | char *text; | |
62e32ac3 | 1148 | struct printk_log *msg; |
116e90b2 | 1149 | int len = 0; |
7ff9554b | 1150 | |
70498253 | 1151 | text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL); |
7ff9554b KS |
1152 | if (!text) |
1153 | return -ENOMEM; | |
1154 | ||
116e90b2 JB |
1155 | while (size > 0) { |
1156 | size_t n; | |
eb02dac9 | 1157 | size_t skip; |
116e90b2 JB |
1158 | |
1159 | raw_spin_lock_irq(&logbuf_lock); | |
1160 | if (syslog_seq < log_first_seq) { | |
1161 | /* messages are gone, move to first one */ | |
1162 | syslog_seq = log_first_seq; | |
1163 | syslog_idx = log_first_idx; | |
5becfb1d | 1164 | syslog_prev = 0; |
eb02dac9 | 1165 | syslog_partial = 0; |
116e90b2 JB |
1166 | } |
1167 | if (syslog_seq == log_next_seq) { | |
1168 | raw_spin_unlock_irq(&logbuf_lock); | |
1169 | break; | |
1170 | } | |
eb02dac9 KS |
1171 | |
1172 | skip = syslog_partial; | |
116e90b2 | 1173 | msg = log_from_idx(syslog_idx); |
70498253 KS |
1174 | n = msg_print_text(msg, syslog_prev, true, text, |
1175 | LOG_LINE_MAX + PREFIX_MAX); | |
eb02dac9 KS |
1176 | if (n - syslog_partial <= size) { |
1177 | /* message fits into buffer, move forward */ | |
116e90b2 JB |
1178 | syslog_idx = log_next(syslog_idx); |
1179 | syslog_seq++; | |
5becfb1d | 1180 | syslog_prev = msg->flags; |
eb02dac9 KS |
1181 | n -= syslog_partial; |
1182 | syslog_partial = 0; | |
1183 | } else if (!len){ | |
1184 | /* partial read(), remember position */ | |
1185 | n = size; | |
1186 | syslog_partial += n; | |
116e90b2 JB |
1187 | } else |
1188 | n = 0; | |
1189 | raw_spin_unlock_irq(&logbuf_lock); | |
1190 | ||
1191 | if (!n) | |
1192 | break; | |
1193 | ||
eb02dac9 | 1194 | if (copy_to_user(buf, text + skip, n)) { |
116e90b2 JB |
1195 | if (!len) |
1196 | len = -EFAULT; | |
1197 | break; | |
1198 | } | |
eb02dac9 KS |
1199 | |
1200 | len += n; | |
1201 | size -= n; | |
1202 | buf += n; | |
7ff9554b | 1203 | } |
7ff9554b KS |
1204 | |
1205 | kfree(text); | |
1206 | return len; | |
1207 | } | |
1208 | ||
1209 | static int syslog_print_all(char __user *buf, int size, bool clear) | |
1210 | { | |
1211 | char *text; | |
1212 | int len = 0; | |
1213 | ||
70498253 | 1214 | text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL); |
7ff9554b KS |
1215 | if (!text) |
1216 | return -ENOMEM; | |
1217 | ||
1218 | raw_spin_lock_irq(&logbuf_lock); | |
1219 | if (buf) { | |
1220 | u64 next_seq; | |
1221 | u64 seq; | |
1222 | u32 idx; | |
5becfb1d | 1223 | enum log_flags prev; |
7ff9554b | 1224 | |
7ff9554b KS |
1225 | /* |
1226 | * Find first record that fits, including all following records, | |
1227 | * into the user-provided buffer for this dump. | |
e2ae715d | 1228 | */ |
7ff9554b KS |
1229 | seq = clear_seq; |
1230 | idx = clear_idx; | |
5becfb1d | 1231 | prev = 0; |
7ff9554b | 1232 | while (seq < log_next_seq) { |
62e32ac3 | 1233 | struct printk_log *msg = log_from_idx(idx); |
3ce9a7c0 | 1234 | |
5becfb1d | 1235 | len += msg_print_text(msg, prev, true, NULL, 0); |
e3756477 | 1236 | prev = msg->flags; |
7ff9554b KS |
1237 | idx = log_next(idx); |
1238 | seq++; | |
1239 | } | |
e2ae715d KS |
1240 | |
1241 | /* move first record forward until length fits into the buffer */ | |
7ff9554b KS |
1242 | seq = clear_seq; |
1243 | idx = clear_idx; | |
5becfb1d | 1244 | prev = 0; |
7ff9554b | 1245 | while (len > size && seq < log_next_seq) { |
62e32ac3 | 1246 | struct printk_log *msg = log_from_idx(idx); |
3ce9a7c0 | 1247 | |
5becfb1d | 1248 | len -= msg_print_text(msg, prev, true, NULL, 0); |
e3756477 | 1249 | prev = msg->flags; |
7ff9554b KS |
1250 | idx = log_next(idx); |
1251 | seq++; | |
1252 | } | |
1253 | ||
e2ae715d | 1254 | /* last message fitting into this dump */ |
7ff9554b KS |
1255 | next_seq = log_next_seq; |
1256 | ||
1257 | len = 0; | |
1258 | while (len >= 0 && seq < next_seq) { | |
62e32ac3 | 1259 | struct printk_log *msg = log_from_idx(idx); |
7ff9554b KS |
1260 | int textlen; |
1261 | ||
70498253 KS |
1262 | textlen = msg_print_text(msg, prev, true, text, |
1263 | LOG_LINE_MAX + PREFIX_MAX); | |
7ff9554b KS |
1264 | if (textlen < 0) { |
1265 | len = textlen; | |
1266 | break; | |
1267 | } | |
1268 | idx = log_next(idx); | |
1269 | seq++; | |
5becfb1d | 1270 | prev = msg->flags; |
7ff9554b KS |
1271 | |
1272 | raw_spin_unlock_irq(&logbuf_lock); | |
1273 | if (copy_to_user(buf + len, text, textlen)) | |
1274 | len = -EFAULT; | |
1275 | else | |
1276 | len += textlen; | |
1277 | raw_spin_lock_irq(&logbuf_lock); | |
1278 | ||
1279 | if (seq < log_first_seq) { | |
1280 | /* messages are gone, move to next one */ | |
1281 | seq = log_first_seq; | |
1282 | idx = log_first_idx; | |
5becfb1d | 1283 | prev = 0; |
7ff9554b KS |
1284 | } |
1285 | } | |
1286 | } | |
1287 | ||
1288 | if (clear) { | |
1289 | clear_seq = log_next_seq; | |
1290 | clear_idx = log_next_idx; | |
1291 | } | |
1292 | raw_spin_unlock_irq(&logbuf_lock); | |
1293 | ||
1294 | kfree(text); | |
1295 | return len; | |
1296 | } | |
1297 | ||
3ea4331c | 1298 | int do_syslog(int type, char __user *buf, int len, int source) |
1da177e4 | 1299 | { |
7ff9554b | 1300 | bool clear = false; |
a39d4a85 | 1301 | static int saved_console_loglevel = LOGLEVEL_DEFAULT; |
ee24aebf | 1302 | int error; |
1da177e4 | 1303 | |
3ea4331c | 1304 | error = check_syslog_permissions(type, source); |
ee24aebf LT |
1305 | if (error) |
1306 | goto out; | |
12b3052c | 1307 | |
1da177e4 | 1308 | switch (type) { |
d78ca3cd | 1309 | case SYSLOG_ACTION_CLOSE: /* Close log */ |
1da177e4 | 1310 | break; |
d78ca3cd | 1311 | case SYSLOG_ACTION_OPEN: /* Open log */ |
1da177e4 | 1312 | break; |
d78ca3cd | 1313 | case SYSLOG_ACTION_READ: /* Read from log */ |
1da177e4 LT |
1314 | error = -EINVAL; |
1315 | if (!buf || len < 0) | |
1316 | goto out; | |
1317 | error = 0; | |
1318 | if (!len) | |
1319 | goto out; | |
1320 | if (!access_ok(VERIFY_WRITE, buf, len)) { | |
1321 | error = -EFAULT; | |
1322 | goto out; | |
1323 | } | |
40dc5651 | 1324 | error = wait_event_interruptible(log_wait, |
7ff9554b | 1325 | syslog_seq != log_next_seq); |
cb424ffe | 1326 | if (error) |
1da177e4 | 1327 | goto out; |
7ff9554b | 1328 | error = syslog_print(buf, len); |
1da177e4 | 1329 | break; |
d78ca3cd KC |
1330 | /* Read/clear last kernel messages */ |
1331 | case SYSLOG_ACTION_READ_CLEAR: | |
7ff9554b | 1332 | clear = true; |
1da177e4 | 1333 | /* FALL THRU */ |
d78ca3cd KC |
1334 | /* Read last kernel messages */ |
1335 | case SYSLOG_ACTION_READ_ALL: | |
1da177e4 LT |
1336 | error = -EINVAL; |
1337 | if (!buf || len < 0) | |
1338 | goto out; | |
1339 | error = 0; | |
1340 | if (!len) | |
1341 | goto out; | |
1342 | if (!access_ok(VERIFY_WRITE, buf, len)) { | |
1343 | error = -EFAULT; | |
1344 | goto out; | |
1345 | } | |
7ff9554b | 1346 | error = syslog_print_all(buf, len, clear); |
1da177e4 | 1347 | break; |
d78ca3cd KC |
1348 | /* Clear ring buffer */ |
1349 | case SYSLOG_ACTION_CLEAR: | |
7ff9554b | 1350 | syslog_print_all(NULL, 0, true); |
4661e356 | 1351 | break; |
d78ca3cd KC |
1352 | /* Disable logging to console */ |
1353 | case SYSLOG_ACTION_CONSOLE_OFF: | |
a39d4a85 | 1354 | if (saved_console_loglevel == LOGLEVEL_DEFAULT) |
1aaad49e | 1355 | saved_console_loglevel = console_loglevel; |
1da177e4 LT |
1356 | console_loglevel = minimum_console_loglevel; |
1357 | break; | |
d78ca3cd KC |
1358 | /* Enable logging to console */ |
1359 | case SYSLOG_ACTION_CONSOLE_ON: | |
a39d4a85 | 1360 | if (saved_console_loglevel != LOGLEVEL_DEFAULT) { |
1aaad49e | 1361 | console_loglevel = saved_console_loglevel; |
a39d4a85 | 1362 | saved_console_loglevel = LOGLEVEL_DEFAULT; |
1aaad49e | 1363 | } |
1da177e4 | 1364 | break; |
d78ca3cd KC |
1365 | /* Set level of messages printed to console */ |
1366 | case SYSLOG_ACTION_CONSOLE_LEVEL: | |
1da177e4 LT |
1367 | error = -EINVAL; |
1368 | if (len < 1 || len > 8) | |
1369 | goto out; | |
1370 | if (len < minimum_console_loglevel) | |
1371 | len = minimum_console_loglevel; | |
1372 | console_loglevel = len; | |
1aaad49e | 1373 | /* Implicitly re-enable logging to console */ |
a39d4a85 | 1374 | saved_console_loglevel = LOGLEVEL_DEFAULT; |
1da177e4 LT |
1375 | error = 0; |
1376 | break; | |
d78ca3cd KC |
1377 | /* Number of chars in the log buffer */ |
1378 | case SYSLOG_ACTION_SIZE_UNREAD: | |
7ff9554b KS |
1379 | raw_spin_lock_irq(&logbuf_lock); |
1380 | if (syslog_seq < log_first_seq) { | |
1381 | /* messages are gone, move to first one */ | |
1382 | syslog_seq = log_first_seq; | |
1383 | syslog_idx = log_first_idx; | |
5becfb1d | 1384 | syslog_prev = 0; |
eb02dac9 | 1385 | syslog_partial = 0; |
7ff9554b | 1386 | } |
3ea4331c | 1387 | if (source == SYSLOG_FROM_PROC) { |
7ff9554b KS |
1388 | /* |
1389 | * Short-cut for poll(/"proc/kmsg") which simply checks | |
1390 | * for pending data, not the size; return the count of | |
1391 | * records, not the length. | |
1392 | */ | |
e97e1267 | 1393 | error = log_next_seq - syslog_seq; |
7ff9554b | 1394 | } else { |
5becfb1d KS |
1395 | u64 seq = syslog_seq; |
1396 | u32 idx = syslog_idx; | |
1397 | enum log_flags prev = syslog_prev; | |
7ff9554b KS |
1398 | |
1399 | error = 0; | |
7ff9554b | 1400 | while (seq < log_next_seq) { |
62e32ac3 | 1401 | struct printk_log *msg = log_from_idx(idx); |
3ce9a7c0 | 1402 | |
5becfb1d | 1403 | error += msg_print_text(msg, prev, true, NULL, 0); |
7ff9554b KS |
1404 | idx = log_next(idx); |
1405 | seq++; | |
5becfb1d | 1406 | prev = msg->flags; |
7ff9554b | 1407 | } |
eb02dac9 | 1408 | error -= syslog_partial; |
7ff9554b KS |
1409 | } |
1410 | raw_spin_unlock_irq(&logbuf_lock); | |
1da177e4 | 1411 | break; |
d78ca3cd KC |
1412 | /* Size of the log buffer */ |
1413 | case SYSLOG_ACTION_SIZE_BUFFER: | |
1da177e4 LT |
1414 | error = log_buf_len; |
1415 | break; | |
1416 | default: | |
1417 | error = -EINVAL; | |
1418 | break; | |
1419 | } | |
1420 | out: | |
1421 | return error; | |
1422 | } | |
1423 | ||
1e7bfb21 | 1424 | SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len) |
1da177e4 | 1425 | { |
637241a9 | 1426 | return do_syslog(type, buf, len, SYSLOG_FROM_READER); |
1da177e4 LT |
1427 | } |
1428 | ||
1da177e4 LT |
1429 | /* |
1430 | * Call the console drivers, asking them to write out | |
1431 | * log_buf[start] to log_buf[end - 1]. | |
ac751efa | 1432 | * The console_lock must be held. |
1da177e4 | 1433 | */ |
6fe29354 TH |
1434 | static void call_console_drivers(int level, |
1435 | const char *ext_text, size_t ext_len, | |
1436 | const char *text, size_t len) | |
1da177e4 | 1437 | { |
7ff9554b | 1438 | struct console *con; |
1da177e4 | 1439 | |
07c65f4d | 1440 | trace_console(text, len); |
7ff9554b KS |
1441 | |
1442 | if (level >= console_loglevel && !ignore_loglevel) | |
1443 | return; | |
1444 | if (!console_drivers) | |
1445 | return; | |
1446 | ||
1447 | for_each_console(con) { | |
1448 | if (exclusive_console && con != exclusive_console) | |
1449 | continue; | |
1450 | if (!(con->flags & CON_ENABLED)) | |
1451 | continue; | |
1452 | if (!con->write) | |
1453 | continue; | |
1454 | if (!cpu_online(smp_processor_id()) && | |
1455 | !(con->flags & CON_ANYTIME)) | |
1456 | continue; | |
6fe29354 TH |
1457 | if (con->flags & CON_EXTENDED) |
1458 | con->write(con, ext_text, ext_len); | |
1459 | else | |
1460 | con->write(con, text, len); | |
7ff9554b | 1461 | } |
1da177e4 LT |
1462 | } |
1463 | ||
1464 | /* | |
205bd3d2 JP |
1465 | * Zap console related locks when oopsing. |
1466 | * To leave time for slow consoles to print a full oops, | |
1467 | * only zap at most once every 30 seconds. | |
1da177e4 LT |
1468 | */ |
1469 | static void zap_locks(void) | |
1470 | { | |
1471 | static unsigned long oops_timestamp; | |
1472 | ||
1473 | if (time_after_eq(jiffies, oops_timestamp) && | |
205bd3d2 | 1474 | !time_after(jiffies, oops_timestamp + 30 * HZ)) |
1da177e4 LT |
1475 | return; |
1476 | ||
1477 | oops_timestamp = jiffies; | |
1478 | ||
94d24fc4 | 1479 | debug_locks_off(); |
1da177e4 | 1480 | /* If a crash is occurring, make sure we can't deadlock */ |
07354eb1 | 1481 | raw_spin_lock_init(&logbuf_lock); |
1da177e4 | 1482 | /* And make sure that we print immediately */ |
5b8c4f23 | 1483 | sema_init(&console_sem, 1); |
1da177e4 LT |
1484 | } |
1485 | ||
af91322e DY |
1486 | int printk_delay_msec __read_mostly; |
1487 | ||
1488 | static inline void printk_delay(void) | |
1489 | { | |
1490 | if (unlikely(printk_delay_msec)) { | |
1491 | int m = printk_delay_msec; | |
1492 | ||
1493 | while (m--) { | |
1494 | mdelay(1); | |
1495 | touch_nmi_watchdog(); | |
1496 | } | |
1497 | } | |
1498 | } | |
1499 | ||
084681d1 KS |
1500 | /* |
1501 | * Continuation lines are buffered, and not committed to the record buffer | |
1502 | * until the line is complete, or a race forces it. The line fragments | |
1503 | * though, are printed immediately to the consoles to ensure everything has | |
1504 | * reached the console in case of a kernel crash. | |
1505 | */ | |
1506 | static struct cont { | |
1507 | char buf[LOG_LINE_MAX]; | |
1508 | size_t len; /* length == 0 means unused buffer */ | |
1509 | size_t cons; /* bytes written to console */ | |
1510 | struct task_struct *owner; /* task of first print*/ | |
1511 | u64 ts_nsec; /* time of first print */ | |
1512 | u8 level; /* log level of first message */ | |
0b90fec3 | 1513 | u8 facility; /* log facility of first message */ |
eab07260 | 1514 | enum log_flags flags; /* prefix, newline flags */ |
084681d1 KS |
1515 | bool flushed:1; /* buffer sealed and committed */ |
1516 | } cont; | |
1517 | ||
70498253 | 1518 | static void cont_flush(enum log_flags flags) |
084681d1 KS |
1519 | { |
1520 | if (cont.flushed) | |
1521 | return; | |
1522 | if (cont.len == 0) | |
1523 | return; | |
1524 | ||
eab07260 KS |
1525 | if (cont.cons) { |
1526 | /* | |
1527 | * If a fragment of this line was directly flushed to the | |
1528 | * console; wait for the console to pick up the rest of the | |
1529 | * line. LOG_NOCONS suppresses a duplicated output. | |
1530 | */ | |
1531 | log_store(cont.facility, cont.level, flags | LOG_NOCONS, | |
1532 | cont.ts_nsec, NULL, 0, cont.buf, cont.len); | |
1533 | cont.flags = flags; | |
1534 | cont.flushed = true; | |
1535 | } else { | |
1536 | /* | |
1537 | * If no fragment of this line ever reached the console, | |
1538 | * just submit it to the store and free the buffer. | |
1539 | */ | |
1540 | log_store(cont.facility, cont.level, flags, 0, | |
1541 | NULL, 0, cont.buf, cont.len); | |
1542 | cont.len = 0; | |
1543 | } | |
084681d1 KS |
1544 | } |
1545 | ||
1546 | static bool cont_add(int facility, int level, const char *text, size_t len) | |
1547 | { | |
1548 | if (cont.len && cont.flushed) | |
1549 | return false; | |
1550 | ||
6fe29354 TH |
1551 | /* |
1552 | * If ext consoles are present, flush and skip in-kernel | |
1553 | * continuation. See nr_ext_console_drivers definition. Also, if | |
1554 | * the line gets too long, split it up in separate records. | |
1555 | */ | |
1556 | if (nr_ext_console_drivers || cont.len + len > sizeof(cont.buf)) { | |
70498253 | 1557 | cont_flush(LOG_CONT); |
084681d1 KS |
1558 | return false; |
1559 | } | |
1560 | ||
1561 | if (!cont.len) { | |
1562 | cont.facility = facility; | |
1563 | cont.level = level; | |
1564 | cont.owner = current; | |
1565 | cont.ts_nsec = local_clock(); | |
eab07260 | 1566 | cont.flags = 0; |
084681d1 KS |
1567 | cont.cons = 0; |
1568 | cont.flushed = false; | |
1569 | } | |
1570 | ||
1571 | memcpy(cont.buf + cont.len, text, len); | |
1572 | cont.len += len; | |
eab07260 KS |
1573 | |
1574 | if (cont.len > (sizeof(cont.buf) * 80) / 100) | |
1575 | cont_flush(LOG_CONT); | |
1576 | ||
084681d1 KS |
1577 | return true; |
1578 | } | |
1579 | ||
1580 | static size_t cont_print_text(char *text, size_t size) | |
1581 | { | |
1582 | size_t textlen = 0; | |
1583 | size_t len; | |
1584 | ||
eab07260 | 1585 | if (cont.cons == 0 && (console_prev & LOG_NEWLINE)) { |
084681d1 KS |
1586 | textlen += print_time(cont.ts_nsec, text); |
1587 | size -= textlen; | |
1588 | } | |
1589 | ||
1590 | len = cont.len - cont.cons; | |
1591 | if (len > 0) { | |
1592 | if (len+1 > size) | |
1593 | len = size-1; | |
1594 | memcpy(text + textlen, cont.buf + cont.cons, len); | |
1595 | textlen += len; | |
1596 | cont.cons = cont.len; | |
1597 | } | |
1598 | ||
1599 | if (cont.flushed) { | |
eab07260 KS |
1600 | if (cont.flags & LOG_NEWLINE) |
1601 | text[textlen++] = '\n'; | |
084681d1 KS |
1602 | /* got everything, release buffer */ |
1603 | cont.len = 0; | |
1604 | } | |
1605 | return textlen; | |
1606 | } | |
1607 | ||
7ff9554b KS |
1608 | asmlinkage int vprintk_emit(int facility, int level, |
1609 | const char *dict, size_t dictlen, | |
1610 | const char *fmt, va_list args) | |
1da177e4 | 1611 | { |
06b031de | 1612 | static bool recursion_bug; |
7ff9554b KS |
1613 | static char textbuf[LOG_LINE_MAX]; |
1614 | char *text = textbuf; | |
458df9fd | 1615 | size_t text_len = 0; |
5becfb1d | 1616 | enum log_flags lflags = 0; |
ac60ad74 | 1617 | unsigned long flags; |
32a76006 | 1618 | int this_cpu; |
7ff9554b | 1619 | int printed_len = 0; |
b522deab | 1620 | int nmi_message_lost; |
458df9fd | 1621 | bool in_sched = false; |
608873ca | 1622 | /* cpu currently holding logbuf_lock in this function */ |
f099755d | 1623 | static unsigned int logbuf_cpu = UINT_MAX; |
608873ca | 1624 | |
a39d4a85 JP |
1625 | if (level == LOGLEVEL_SCHED) { |
1626 | level = LOGLEVEL_DEFAULT; | |
458df9fd SR |
1627 | in_sched = true; |
1628 | } | |
1da177e4 | 1629 | |
2fa72c8f | 1630 | boot_delay_msec(level); |
af91322e | 1631 | printk_delay(); |
bfe8df3d | 1632 | |
1a9a8aef | 1633 | local_irq_save(flags); |
32a76006 IM |
1634 | this_cpu = smp_processor_id(); |
1635 | ||
1636 | /* | |
1637 | * Ouch, printk recursed into itself! | |
1638 | */ | |
7ff9554b | 1639 | if (unlikely(logbuf_cpu == this_cpu)) { |
32a76006 IM |
1640 | /* |
1641 | * If a crash is occurring during printk() on this CPU, | |
1642 | * then try to get the crash message out but make sure | |
1643 | * we can't deadlock. Otherwise just return to avoid the | |
1644 | * recursion and return - but flag the recursion so that | |
1645 | * it can be printed at the next appropriate moment: | |
1646 | */ | |
94d24fc4 | 1647 | if (!oops_in_progress && !lockdep_recursing(current)) { |
06b031de | 1648 | recursion_bug = true; |
5874af20 JK |
1649 | local_irq_restore(flags); |
1650 | return 0; | |
32a76006 IM |
1651 | } |
1652 | zap_locks(); | |
1653 | } | |
1654 | ||
a0f1ccfd | 1655 | lockdep_off(); |
a8199371 | 1656 | /* This stops the holder of console_sem just where we want him */ |
07354eb1 | 1657 | raw_spin_lock(&logbuf_lock); |
7ff9554b | 1658 | logbuf_cpu = this_cpu; |
1da177e4 | 1659 | |
000a7d66 | 1660 | if (unlikely(recursion_bug)) { |
7ff9554b KS |
1661 | static const char recursion_msg[] = |
1662 | "BUG: recent printk recursion!"; | |
1663 | ||
06b031de | 1664 | recursion_bug = false; |
7ff9554b | 1665 | /* emit KERN_CRIT message */ |
034633cc | 1666 | printed_len += log_store(0, 2, LOG_PREFIX|LOG_NEWLINE, 0, |
000a7d66 PP |
1667 | NULL, 0, recursion_msg, |
1668 | strlen(recursion_msg)); | |
32a76006 | 1669 | } |
1da177e4 | 1670 | |
b522deab PM |
1671 | nmi_message_lost = get_nmi_message_lost(); |
1672 | if (unlikely(nmi_message_lost)) { | |
1673 | text_len = scnprintf(textbuf, sizeof(textbuf), | |
1674 | "BAD LUCK: lost %d message(s) from NMI context!", | |
1675 | nmi_message_lost); | |
1676 | printed_len += log_store(0, 2, LOG_PREFIX|LOG_NEWLINE, 0, | |
1677 | NULL, 0, textbuf, text_len); | |
1678 | } | |
1679 | ||
7ff9554b KS |
1680 | /* |
1681 | * The printf needs to come first; we need the syslog | |
1682 | * prefix which might be passed-in as a parameter. | |
1683 | */ | |
98e35f58 | 1684 | text_len = vscnprintf(text, sizeof(textbuf), fmt, args); |
5fd29d6c | 1685 | |
7ff9554b | 1686 | /* mark and strip a trailing newline */ |
c313af14 KS |
1687 | if (text_len && text[text_len-1] == '\n') { |
1688 | text_len--; | |
5becfb1d | 1689 | lflags |= LOG_NEWLINE; |
7ff9554b | 1690 | } |
9d90c8d9 | 1691 | |
088a52aa JP |
1692 | /* strip kernel syslog prefix and extract log level or control flags */ |
1693 | if (facility == 0) { | |
1694 | int kern_level = printk_get_level(text); | |
1695 | ||
1696 | if (kern_level) { | |
1697 | const char *end_of_header = printk_skip_level(text); | |
1698 | switch (kern_level) { | |
1699 | case '0' ... '7': | |
a39d4a85 | 1700 | if (level == LOGLEVEL_DEFAULT) |
088a52aa | 1701 | level = kern_level - '0'; |
a39d4a85 | 1702 | /* fallthrough */ |
088a52aa JP |
1703 | case 'd': /* KERN_DEFAULT */ |
1704 | lflags |= LOG_PREFIX; | |
088a52aa | 1705 | } |
e8c42d36 PM |
1706 | /* |
1707 | * No need to check length here because vscnprintf | |
1708 | * put '\0' at the end of the string. Only valid and | |
1709 | * newly printed level is detected. | |
1710 | */ | |
088a52aa JP |
1711 | text_len -= end_of_header - text; |
1712 | text = (char *)end_of_header; | |
5fd29d6c LT |
1713 | } |
1714 | } | |
1715 | ||
a39d4a85 | 1716 | if (level == LOGLEVEL_DEFAULT) |
c313af14 | 1717 | level = default_message_loglevel; |
9d90c8d9 | 1718 | |
5becfb1d KS |
1719 | if (dict) |
1720 | lflags |= LOG_PREFIX|LOG_NEWLINE; | |
ac60ad74 | 1721 | |
5becfb1d | 1722 | if (!(lflags & LOG_NEWLINE)) { |
084681d1 KS |
1723 | /* |
1724 | * Flush the conflicting buffer. An earlier newline was missing, | |
1725 | * or another task also prints continuation lines. | |
1726 | */ | |
5becfb1d | 1727 | if (cont.len && (lflags & LOG_PREFIX || cont.owner != current)) |
eab07260 | 1728 | cont_flush(LOG_NEWLINE); |
c313af14 | 1729 | |
084681d1 | 1730 | /* buffer line if possible, otherwise store it right away */ |
034633cc PM |
1731 | if (cont_add(facility, level, text, text_len)) |
1732 | printed_len += text_len; | |
1733 | else | |
1734 | printed_len += log_store(facility, level, | |
1735 | lflags | LOG_CONT, 0, | |
1736 | dict, dictlen, text, text_len); | |
5c5d5ca5 | 1737 | } else { |
084681d1 | 1738 | bool stored = false; |
c313af14 | 1739 | |
084681d1 | 1740 | /* |
d3620822 SR |
1741 | * If an earlier newline was missing and it was the same task, |
1742 | * either merge it with the current buffer and flush, or if | |
1743 | * there was a race with interrupts (prefix == true) then just | |
1744 | * flush it out and store this line separately. | |
1d3fa370 AK |
1745 | * If the preceding printk was from a different task and missed |
1746 | * a newline, flush and append the newline. | |
084681d1 | 1747 | */ |
1d3fa370 AK |
1748 | if (cont.len) { |
1749 | if (cont.owner == current && !(lflags & LOG_PREFIX)) | |
1750 | stored = cont_add(facility, level, text, | |
1751 | text_len); | |
eab07260 | 1752 | cont_flush(LOG_NEWLINE); |
c313af14 | 1753 | } |
084681d1 | 1754 | |
034633cc PM |
1755 | if (stored) |
1756 | printed_len += text_len; | |
1757 | else | |
1758 | printed_len += log_store(facility, level, lflags, 0, | |
1759 | dict, dictlen, text, text_len); | |
1da177e4 LT |
1760 | } |
1761 | ||
608873ca JK |
1762 | logbuf_cpu = UINT_MAX; |
1763 | raw_spin_unlock(&logbuf_lock); | |
5874af20 JK |
1764 | lockdep_on(); |
1765 | local_irq_restore(flags); | |
939f04be | 1766 | |
458df9fd | 1767 | /* If called from the scheduler, we can not call up(). */ |
d18bbc21 | 1768 | if (!in_sched) { |
5874af20 | 1769 | lockdep_off(); |
d18bbc21 AM |
1770 | /* |
1771 | * Try to acquire and then immediately release the console | |
1772 | * semaphore. The release will print out buffers and wake up | |
1773 | * /dev/kmsg and syslog() users. | |
1774 | */ | |
a8199371 | 1775 | if (console_trylock()) |
d18bbc21 | 1776 | console_unlock(); |
5874af20 | 1777 | lockdep_on(); |
d18bbc21 | 1778 | } |
76a8ad29 | 1779 | |
1da177e4 LT |
1780 | return printed_len; |
1781 | } | |
7ff9554b KS |
1782 | EXPORT_SYMBOL(vprintk_emit); |
1783 | ||
1784 | asmlinkage int vprintk(const char *fmt, va_list args) | |
1785 | { | |
a39d4a85 | 1786 | return vprintk_emit(0, LOGLEVEL_DEFAULT, NULL, 0, fmt, args); |
7ff9554b | 1787 | } |
1da177e4 LT |
1788 | EXPORT_SYMBOL(vprintk); |
1789 | ||
7ff9554b KS |
1790 | asmlinkage int printk_emit(int facility, int level, |
1791 | const char *dict, size_t dictlen, | |
1792 | const char *fmt, ...) | |
1793 | { | |
1794 | va_list args; | |
1795 | int r; | |
1796 | ||
1797 | va_start(args, fmt); | |
1798 | r = vprintk_emit(facility, level, dict, dictlen, fmt, args); | |
1799 | va_end(args); | |
1800 | ||
1801 | return r; | |
1802 | } | |
1803 | EXPORT_SYMBOL(printk_emit); | |
1804 | ||
afdc34a3 SRRH |
1805 | int vprintk_default(const char *fmt, va_list args) |
1806 | { | |
1807 | int r; | |
1808 | ||
1809 | #ifdef CONFIG_KGDB_KDB | |
1810 | if (unlikely(kdb_trap_printk)) { | |
f7d4ca8b | 1811 | r = vkdb_printf(KDB_MSGSRC_PRINTK, fmt, args); |
afdc34a3 SRRH |
1812 | return r; |
1813 | } | |
1814 | #endif | |
350e4f49 | 1815 | r = vprintk_emit(0, LOGLEVEL_DEFAULT, NULL, 0, fmt, args); |
afdc34a3 SRRH |
1816 | |
1817 | return r; | |
1818 | } | |
1819 | EXPORT_SYMBOL_GPL(vprintk_default); | |
1820 | ||
7ff9554b KS |
1821 | /** |
1822 | * printk - print a kernel message | |
1823 | * @fmt: format string | |
1824 | * | |
1825 | * This is printk(). It can be called from any context. We want it to work. | |
1826 | * | |
1827 | * We try to grab the console_lock. If we succeed, it's easy - we log the | |
1828 | * output and call the console drivers. If we fail to get the semaphore, we | |
1829 | * place the output into the log buffer and return. The current holder of | |
1830 | * the console_sem will notice the new output in console_unlock(); and will | |
1831 | * send it to the consoles before releasing the lock. | |
1832 | * | |
1833 | * One effect of this deferred printing is that code which calls printk() and | |
1834 | * then changes console_loglevel may break. This is because console_loglevel | |
1835 | * is inspected when the actual printing occurs. | |
1836 | * | |
1837 | * See also: | |
1838 | * printf(3) | |
1839 | * | |
1840 | * See the vsnprintf() documentation for format string extensions over C99. | |
1841 | */ | |
722a9f92 | 1842 | asmlinkage __visible int printk(const char *fmt, ...) |
7ff9554b KS |
1843 | { |
1844 | va_list args; | |
1845 | int r; | |
1846 | ||
7ff9554b | 1847 | va_start(args, fmt); |
afdc34a3 | 1848 | r = vprintk_func(fmt, args); |
7ff9554b KS |
1849 | va_end(args); |
1850 | ||
1851 | return r; | |
1852 | } | |
1853 | EXPORT_SYMBOL(printk); | |
7f3a781d | 1854 | |
96efedf1 | 1855 | #else /* CONFIG_PRINTK */ |
d59745ce | 1856 | |
70498253 KS |
1857 | #define LOG_LINE_MAX 0 |
1858 | #define PREFIX_MAX 0 | |
249771b8 | 1859 | |
96efedf1 KS |
1860 | static u64 syslog_seq; |
1861 | static u32 syslog_idx; | |
eab07260 KS |
1862 | static u64 console_seq; |
1863 | static u32 console_idx; | |
96efedf1 KS |
1864 | static enum log_flags syslog_prev; |
1865 | static u64 log_first_seq; | |
1866 | static u32 log_first_idx; | |
1867 | static u64 log_next_seq; | |
eab07260 | 1868 | static enum log_flags console_prev; |
084681d1 KS |
1869 | static struct cont { |
1870 | size_t len; | |
1871 | size_t cons; | |
1872 | u8 level; | |
1873 | bool flushed:1; | |
1874 | } cont; | |
6fe29354 TH |
1875 | static char *log_text(const struct printk_log *msg) { return NULL; } |
1876 | static char *log_dict(const struct printk_log *msg) { return NULL; } | |
62e32ac3 | 1877 | static struct printk_log *log_from_idx(u32 idx) { return NULL; } |
7f3a781d | 1878 | static u32 log_next(u32 idx) { return 0; } |
6fe29354 TH |
1879 | static ssize_t msg_print_ext_header(char *buf, size_t size, |
1880 | struct printk_log *msg, u64 seq, | |
1881 | enum log_flags prev_flags) { return 0; } | |
1882 | static ssize_t msg_print_ext_body(char *buf, size_t size, | |
1883 | char *dict, size_t dict_len, | |
1884 | char *text, size_t text_len) { return 0; } | |
1885 | static void call_console_drivers(int level, | |
1886 | const char *ext_text, size_t ext_len, | |
1887 | const char *text, size_t len) {} | |
62e32ac3 | 1888 | static size_t msg_print_text(const struct printk_log *msg, enum log_flags prev, |
5becfb1d | 1889 | bool syslog, char *buf, size_t size) { return 0; } |
084681d1 | 1890 | static size_t cont_print_text(char *text, size_t size) { return 0; } |
d59745ce | 1891 | |
04b74b27 SRRH |
1892 | /* Still needs to be defined for users */ |
1893 | DEFINE_PER_CPU(printk_func_t, printk_func); | |
1894 | ||
7f3a781d | 1895 | #endif /* CONFIG_PRINTK */ |
d59745ce | 1896 | |
d0380e6c TG |
1897 | #ifdef CONFIG_EARLY_PRINTK |
1898 | struct console *early_console; | |
1899 | ||
722a9f92 | 1900 | asmlinkage __visible void early_printk(const char *fmt, ...) |
d0380e6c TG |
1901 | { |
1902 | va_list ap; | |
1dc6244b JP |
1903 | char buf[512]; |
1904 | int n; | |
1905 | ||
1906 | if (!early_console) | |
1907 | return; | |
d0380e6c TG |
1908 | |
1909 | va_start(ap, fmt); | |
1dc6244b | 1910 | n = vscnprintf(buf, sizeof(buf), fmt, ap); |
d0380e6c | 1911 | va_end(ap); |
1dc6244b JP |
1912 | |
1913 | early_console->write(early_console, buf, n); | |
d0380e6c TG |
1914 | } |
1915 | #endif | |
1916 | ||
f7511d5f ST |
1917 | static int __add_preferred_console(char *name, int idx, char *options, |
1918 | char *brl_options) | |
1919 | { | |
1920 | struct console_cmdline *c; | |
1921 | int i; | |
1922 | ||
1923 | /* | |
1924 | * See if this tty is not yet registered, and | |
1925 | * if we have a slot free. | |
1926 | */ | |
23475408 JP |
1927 | for (i = 0, c = console_cmdline; |
1928 | i < MAX_CMDLINECONSOLES && c->name[0]; | |
1929 | i++, c++) { | |
1930 | if (strcmp(c->name, name) == 0 && c->index == idx) { | |
1931 | if (!brl_options) | |
1932 | selected_console = i; | |
1933 | return 0; | |
f7511d5f | 1934 | } |
23475408 | 1935 | } |
f7511d5f ST |
1936 | if (i == MAX_CMDLINECONSOLES) |
1937 | return -E2BIG; | |
1938 | if (!brl_options) | |
1939 | selected_console = i; | |
f7511d5f ST |
1940 | strlcpy(c->name, name, sizeof(c->name)); |
1941 | c->options = options; | |
bbeddf52 JP |
1942 | braille_set_options(c, brl_options); |
1943 | ||
f7511d5f ST |
1944 | c->index = idx; |
1945 | return 0; | |
1946 | } | |
2ea1c539 | 1947 | /* |
0b90fec3 AE |
1948 | * Set up a console. Called via do_early_param() in init/main.c |
1949 | * for each "console=" parameter in the boot command line. | |
2ea1c539 JB |
1950 | */ |
1951 | static int __init console_setup(char *str) | |
1952 | { | |
0b90fec3 | 1953 | char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for "ttyS" */ |
f7511d5f | 1954 | char *s, *options, *brl_options = NULL; |
2ea1c539 JB |
1955 | int idx; |
1956 | ||
bbeddf52 JP |
1957 | if (_braille_console_setup(&str, &brl_options)) |
1958 | return 1; | |
f7511d5f | 1959 | |
2ea1c539 JB |
1960 | /* |
1961 | * Decode str into name, index, options. | |
1962 | */ | |
1963 | if (str[0] >= '0' && str[0] <= '9') { | |
eaa944af YL |
1964 | strcpy(buf, "ttyS"); |
1965 | strncpy(buf + 4, str, sizeof(buf) - 5); | |
2ea1c539 | 1966 | } else { |
eaa944af | 1967 | strncpy(buf, str, sizeof(buf) - 1); |
2ea1c539 | 1968 | } |
eaa944af | 1969 | buf[sizeof(buf) - 1] = 0; |
249771b8 AE |
1970 | options = strchr(str, ','); |
1971 | if (options) | |
2ea1c539 JB |
1972 | *(options++) = 0; |
1973 | #ifdef __sparc__ | |
1974 | if (!strcmp(str, "ttya")) | |
eaa944af | 1975 | strcpy(buf, "ttyS0"); |
2ea1c539 | 1976 | if (!strcmp(str, "ttyb")) |
eaa944af | 1977 | strcpy(buf, "ttyS1"); |
2ea1c539 | 1978 | #endif |
eaa944af | 1979 | for (s = buf; *s; s++) |
249771b8 | 1980 | if (isdigit(*s) || *s == ',') |
2ea1c539 JB |
1981 | break; |
1982 | idx = simple_strtoul(s, NULL, 10); | |
1983 | *s = 0; | |
1984 | ||
f7511d5f | 1985 | __add_preferred_console(buf, idx, options, brl_options); |
9e124fe1 | 1986 | console_set_on_cmdline = 1; |
2ea1c539 JB |
1987 | return 1; |
1988 | } | |
1989 | __setup("console=", console_setup); | |
1990 | ||
3c0547ba MM |
1991 | /** |
1992 | * add_preferred_console - add a device to the list of preferred consoles. | |
ddad86c2 MW |
1993 | * @name: device name |
1994 | * @idx: device index | |
1995 | * @options: options for this console | |
3c0547ba MM |
1996 | * |
1997 | * The last preferred console added will be used for kernel messages | |
1998 | * and stdin/out/err for init. Normally this is used by console_setup | |
1999 | * above to handle user-supplied console arguments; however it can also | |
2000 | * be used by arch-specific code either to override the user or more | |
2001 | * commonly to provide a default console (ie from PROM variables) when | |
2002 | * the user has not supplied one. | |
2003 | */ | |
fb445ee5 | 2004 | int add_preferred_console(char *name, int idx, char *options) |
3c0547ba | 2005 | { |
f7511d5f | 2006 | return __add_preferred_console(name, idx, options, NULL); |
3c0547ba MM |
2007 | } |
2008 | ||
d25d9fec | 2009 | bool console_suspend_enabled = true; |
8f4ce8c3 AS |
2010 | EXPORT_SYMBOL(console_suspend_enabled); |
2011 | ||
2012 | static int __init console_suspend_disable(char *str) | |
2013 | { | |
d25d9fec | 2014 | console_suspend_enabled = false; |
8f4ce8c3 AS |
2015 | return 1; |
2016 | } | |
2017 | __setup("no_console_suspend", console_suspend_disable); | |
134620f7 YZ |
2018 | module_param_named(console_suspend, console_suspend_enabled, |
2019 | bool, S_IRUGO | S_IWUSR); | |
2020 | MODULE_PARM_DESC(console_suspend, "suspend console during suspend" | |
2021 | " and hibernate operations"); | |
8f4ce8c3 | 2022 | |
557240b4 LT |
2023 | /** |
2024 | * suspend_console - suspend the console subsystem | |
2025 | * | |
2026 | * This disables printk() while we go into suspend states | |
2027 | */ | |
2028 | void suspend_console(void) | |
2029 | { | |
8f4ce8c3 AS |
2030 | if (!console_suspend_enabled) |
2031 | return; | |
0d63081d | 2032 | printk("Suspending console(s) (use no_console_suspend to debug)\n"); |
ac751efa | 2033 | console_lock(); |
557240b4 | 2034 | console_suspended = 1; |
bd8d7cf5 | 2035 | up_console_sem(); |
557240b4 LT |
2036 | } |
2037 | ||
2038 | void resume_console(void) | |
2039 | { | |
8f4ce8c3 AS |
2040 | if (!console_suspend_enabled) |
2041 | return; | |
bd8d7cf5 | 2042 | down_console_sem(); |
557240b4 | 2043 | console_suspended = 0; |
ac751efa | 2044 | console_unlock(); |
557240b4 LT |
2045 | } |
2046 | ||
034260d6 KC |
2047 | /** |
2048 | * console_cpu_notify - print deferred console messages after CPU hotplug | |
2049 | * @self: notifier struct | |
2050 | * @action: CPU hotplug event | |
2051 | * @hcpu: unused | |
2052 | * | |
2053 | * If printk() is called from a CPU that is not online yet, the messages | |
2054 | * will be spooled but will not show up on the console. This function is | |
2055 | * called when a new CPU comes online (or fails to come up), and ensures | |
2056 | * that any such output gets printed. | |
2057 | */ | |
0db0628d | 2058 | static int console_cpu_notify(struct notifier_block *self, |
034260d6 KC |
2059 | unsigned long action, void *hcpu) |
2060 | { | |
2061 | switch (action) { | |
2062 | case CPU_ONLINE: | |
2063 | case CPU_DEAD: | |
034260d6 KC |
2064 | case CPU_DOWN_FAILED: |
2065 | case CPU_UP_CANCELED: | |
ac751efa TH |
2066 | console_lock(); |
2067 | console_unlock(); | |
034260d6 KC |
2068 | } |
2069 | return NOTIFY_OK; | |
2070 | } | |
2071 | ||
1da177e4 | 2072 | /** |
ac751efa | 2073 | * console_lock - lock the console system for exclusive use. |
1da177e4 | 2074 | * |
ac751efa | 2075 | * Acquires a lock which guarantees that the caller has |
1da177e4 LT |
2076 | * exclusive access to the console system and the console_drivers list. |
2077 | * | |
2078 | * Can sleep, returns nothing. | |
2079 | */ | |
ac751efa | 2080 | void console_lock(void) |
1da177e4 | 2081 | { |
6b898c07 DV |
2082 | might_sleep(); |
2083 | ||
bd8d7cf5 | 2084 | down_console_sem(); |
403f3075 AH |
2085 | if (console_suspended) |
2086 | return; | |
1da177e4 LT |
2087 | console_locked = 1; |
2088 | console_may_schedule = 1; | |
2089 | } | |
ac751efa | 2090 | EXPORT_SYMBOL(console_lock); |
1da177e4 | 2091 | |
ac751efa TH |
2092 | /** |
2093 | * console_trylock - try to lock the console system for exclusive use. | |
2094 | * | |
0b90fec3 AE |
2095 | * Try to acquire a lock which guarantees that the caller has exclusive |
2096 | * access to the console system and the console_drivers list. | |
ac751efa TH |
2097 | * |
2098 | * returns 1 on success, and 0 on failure to acquire the lock. | |
2099 | */ | |
2100 | int console_trylock(void) | |
1da177e4 | 2101 | { |
bd8d7cf5 | 2102 | if (down_trylock_console_sem()) |
ac751efa | 2103 | return 0; |
403f3075 | 2104 | if (console_suspended) { |
bd8d7cf5 | 2105 | up_console_sem(); |
ac751efa | 2106 | return 0; |
403f3075 | 2107 | } |
1da177e4 | 2108 | console_locked = 1; |
6b97a20d SS |
2109 | /* |
2110 | * When PREEMPT_COUNT disabled we can't reliably detect if it's | |
2111 | * safe to schedule (e.g. calling printk while holding a spin_lock), | |
2112 | * because preempt_disable()/preempt_enable() are just barriers there | |
2113 | * and preempt_count() is always 0. | |
2114 | * | |
2115 | * RCU read sections have a separate preemption counter when | |
2116 | * PREEMPT_RCU enabled thus we must take extra care and check | |
2117 | * rcu_preempt_depth(), otherwise RCU read sections modify | |
2118 | * preempt_count(). | |
2119 | */ | |
2120 | console_may_schedule = !oops_in_progress && | |
2121 | preemptible() && | |
2122 | !rcu_preempt_depth(); | |
ac751efa | 2123 | return 1; |
1da177e4 | 2124 | } |
ac751efa | 2125 | EXPORT_SYMBOL(console_trylock); |
1da177e4 LT |
2126 | |
2127 | int is_console_locked(void) | |
2128 | { | |
2129 | return console_locked; | |
2130 | } | |
1da177e4 | 2131 | |
a8199371 SS |
2132 | /* |
2133 | * Check if we have any console that is capable of printing while cpu is | |
2134 | * booting or shutting down. Requires console_sem. | |
2135 | */ | |
2136 | static int have_callable_console(void) | |
2137 | { | |
2138 | struct console *con; | |
2139 | ||
2140 | for_each_console(con) | |
adaf6590 SS |
2141 | if ((con->flags & CON_ENABLED) && |
2142 | (con->flags & CON_ANYTIME)) | |
a8199371 SS |
2143 | return 1; |
2144 | ||
2145 | return 0; | |
2146 | } | |
2147 | ||
2148 | /* | |
2149 | * Can we actually use the console at this time on this cpu? | |
2150 | * | |
2151 | * Console drivers may assume that per-cpu resources have been allocated. So | |
2152 | * unless they're explicitly marked as being able to cope (CON_ANYTIME) don't | |
2153 | * call them until this CPU is officially up. | |
2154 | */ | |
2155 | static inline int can_use_console(void) | |
2156 | { | |
2157 | return cpu_online(raw_smp_processor_id()) || have_callable_console(); | |
2158 | } | |
2159 | ||
eab07260 KS |
2160 | static void console_cont_flush(char *text, size_t size) |
2161 | { | |
2162 | unsigned long flags; | |
2163 | size_t len; | |
2164 | ||
2165 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2166 | ||
2167 | if (!cont.len) | |
2168 | goto out; | |
2169 | ||
2170 | /* | |
2171 | * We still queue earlier records, likely because the console was | |
2172 | * busy. The earlier ones need to be printed before this one, we | |
2173 | * did not flush any fragment so far, so just let it queue up. | |
2174 | */ | |
2175 | if (console_seq < log_next_seq && !cont.cons) | |
2176 | goto out; | |
2177 | ||
2178 | len = cont_print_text(text, size); | |
2179 | raw_spin_unlock(&logbuf_lock); | |
2180 | stop_critical_timings(); | |
6fe29354 | 2181 | call_console_drivers(cont.level, NULL, 0, text, len); |
eab07260 KS |
2182 | start_critical_timings(); |
2183 | local_irq_restore(flags); | |
2184 | return; | |
2185 | out: | |
2186 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2187 | } | |
7ff9554b | 2188 | |
1da177e4 | 2189 | /** |
ac751efa | 2190 | * console_unlock - unlock the console system |
1da177e4 | 2191 | * |
ac751efa | 2192 | * Releases the console_lock which the caller holds on the console system |
1da177e4 LT |
2193 | * and the console driver list. |
2194 | * | |
ac751efa TH |
2195 | * While the console_lock was held, console output may have been buffered |
2196 | * by printk(). If this is the case, console_unlock(); emits | |
2197 | * the output prior to releasing the lock. | |
1da177e4 | 2198 | * |
7f3a781d | 2199 | * If there is output waiting, we wake /dev/kmsg and syslog() users. |
1da177e4 | 2200 | * |
ac751efa | 2201 | * console_unlock(); may be called from any context. |
1da177e4 | 2202 | */ |
ac751efa | 2203 | void console_unlock(void) |
1da177e4 | 2204 | { |
6fe29354 | 2205 | static char ext_text[CONSOLE_EXT_LOG_MAX]; |
70498253 | 2206 | static char text[LOG_LINE_MAX + PREFIX_MAX]; |
7ff9554b | 2207 | static u64 seen_seq; |
1da177e4 | 2208 | unsigned long flags; |
7ff9554b | 2209 | bool wake_klogd = false; |
8d91f8b1 | 2210 | bool do_cond_resched, retry; |
1da177e4 | 2211 | |
557240b4 | 2212 | if (console_suspended) { |
bd8d7cf5 | 2213 | up_console_sem(); |
557240b4 LT |
2214 | return; |
2215 | } | |
78944e54 | 2216 | |
8d91f8b1 TH |
2217 | /* |
2218 | * Console drivers are called under logbuf_lock, so | |
2219 | * @console_may_schedule should be cleared before; however, we may | |
2220 | * end up dumping a lot of lines, for example, if called from | |
2221 | * console registration path, and should invoke cond_resched() | |
2222 | * between lines if allowable. Not doing so can cause a very long | |
2223 | * scheduling stall on a slow console leading to RCU stall and | |
2224 | * softlockup warnings which exacerbate the issue with more | |
2225 | * messages practically incapacitating the system. | |
2226 | */ | |
2227 | do_cond_resched = console_may_schedule; | |
78944e54 AD |
2228 | console_may_schedule = 0; |
2229 | ||
a8199371 SS |
2230 | again: |
2231 | /* | |
2232 | * We released the console_sem lock, so we need to recheck if | |
2233 | * cpu is online and (if not) is there at least one CON_ANYTIME | |
2234 | * console. | |
2235 | */ | |
2236 | if (!can_use_console()) { | |
2237 | console_locked = 0; | |
2238 | up_console_sem(); | |
2239 | return; | |
2240 | } | |
2241 | ||
084681d1 | 2242 | /* flush buffered message fragment immediately to console */ |
eab07260 | 2243 | console_cont_flush(text, sizeof(text)); |
a8199371 | 2244 | |
7ff9554b | 2245 | for (;;) { |
62e32ac3 | 2246 | struct printk_log *msg; |
6fe29354 | 2247 | size_t ext_len = 0; |
3ce9a7c0 | 2248 | size_t len; |
7ff9554b KS |
2249 | int level; |
2250 | ||
07354eb1 | 2251 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
7ff9554b KS |
2252 | if (seen_seq != log_next_seq) { |
2253 | wake_klogd = true; | |
2254 | seen_seq = log_next_seq; | |
2255 | } | |
2256 | ||
2257 | if (console_seq < log_first_seq) { | |
84b5ec8a WD |
2258 | len = sprintf(text, "** %u printk messages dropped ** ", |
2259 | (unsigned)(log_first_seq - console_seq)); | |
2260 | ||
7ff9554b KS |
2261 | /* messages are gone, move to first one */ |
2262 | console_seq = log_first_seq; | |
2263 | console_idx = log_first_idx; | |
5becfb1d | 2264 | console_prev = 0; |
84b5ec8a WD |
2265 | } else { |
2266 | len = 0; | |
7ff9554b | 2267 | } |
084681d1 | 2268 | skip: |
7ff9554b KS |
2269 | if (console_seq == log_next_seq) |
2270 | break; | |
2271 | ||
2272 | msg = log_from_idx(console_idx); | |
084681d1 KS |
2273 | if (msg->flags & LOG_NOCONS) { |
2274 | /* | |
2275 | * Skip record we have buffered and already printed | |
2276 | * directly to the console when we received it. | |
2277 | */ | |
2278 | console_idx = log_next(console_idx); | |
2279 | console_seq++; | |
68b6507d KS |
2280 | /* |
2281 | * We will get here again when we register a new | |
2282 | * CON_PRINTBUFFER console. Clear the flag so we | |
2283 | * will properly dump everything later. | |
2284 | */ | |
2285 | msg->flags &= ~LOG_NOCONS; | |
eab07260 | 2286 | console_prev = msg->flags; |
084681d1 KS |
2287 | goto skip; |
2288 | } | |
649e6ee3 | 2289 | |
084681d1 | 2290 | level = msg->level; |
84b5ec8a WD |
2291 | len += msg_print_text(msg, console_prev, false, |
2292 | text + len, sizeof(text) - len); | |
6fe29354 TH |
2293 | if (nr_ext_console_drivers) { |
2294 | ext_len = msg_print_ext_header(ext_text, | |
2295 | sizeof(ext_text), | |
2296 | msg, console_seq, console_prev); | |
2297 | ext_len += msg_print_ext_body(ext_text + ext_len, | |
2298 | sizeof(ext_text) - ext_len, | |
2299 | log_dict(msg), msg->dict_len, | |
2300 | log_text(msg), msg->text_len); | |
2301 | } | |
7ff9554b KS |
2302 | console_idx = log_next(console_idx); |
2303 | console_seq++; | |
5becfb1d | 2304 | console_prev = msg->flags; |
07354eb1 | 2305 | raw_spin_unlock(&logbuf_lock); |
7ff9554b | 2306 | |
81d68a96 | 2307 | stop_critical_timings(); /* don't trace print latency */ |
6fe29354 | 2308 | call_console_drivers(level, ext_text, ext_len, text, len); |
81d68a96 | 2309 | start_critical_timings(); |
1da177e4 | 2310 | local_irq_restore(flags); |
8d91f8b1 TH |
2311 | |
2312 | if (do_cond_resched) | |
2313 | cond_resched(); | |
1da177e4 LT |
2314 | } |
2315 | console_locked = 0; | |
fe3d8ad3 FT |
2316 | |
2317 | /* Release the exclusive_console once it is used */ | |
2318 | if (unlikely(exclusive_console)) | |
2319 | exclusive_console = NULL; | |
2320 | ||
07354eb1 | 2321 | raw_spin_unlock(&logbuf_lock); |
4f2a8d3c | 2322 | |
bd8d7cf5 | 2323 | up_console_sem(); |
4f2a8d3c PZ |
2324 | |
2325 | /* | |
2326 | * Someone could have filled up the buffer again, so re-check if there's | |
2327 | * something to flush. In case we cannot trylock the console_sem again, | |
2328 | * there's a new owner and the console_unlock() from them will do the | |
2329 | * flush, no worries. | |
2330 | */ | |
07354eb1 | 2331 | raw_spin_lock(&logbuf_lock); |
7ff9554b | 2332 | retry = console_seq != log_next_seq; |
09dc3cf9 PZ |
2333 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
2334 | ||
4f2a8d3c PZ |
2335 | if (retry && console_trylock()) |
2336 | goto again; | |
2337 | ||
e3e8a75d KK |
2338 | if (wake_klogd) |
2339 | wake_up_klogd(); | |
1da177e4 | 2340 | } |
ac751efa | 2341 | EXPORT_SYMBOL(console_unlock); |
1da177e4 | 2342 | |
ddad86c2 MW |
2343 | /** |
2344 | * console_conditional_schedule - yield the CPU if required | |
1da177e4 LT |
2345 | * |
2346 | * If the console code is currently allowed to sleep, and | |
2347 | * if this CPU should yield the CPU to another task, do | |
2348 | * so here. | |
2349 | * | |
ac751efa | 2350 | * Must be called within console_lock();. |
1da177e4 LT |
2351 | */ |
2352 | void __sched console_conditional_schedule(void) | |
2353 | { | |
2354 | if (console_may_schedule) | |
2355 | cond_resched(); | |
2356 | } | |
2357 | EXPORT_SYMBOL(console_conditional_schedule); | |
2358 | ||
1da177e4 LT |
2359 | void console_unblank(void) |
2360 | { | |
2361 | struct console *c; | |
2362 | ||
2363 | /* | |
2364 | * console_unblank can no longer be called in interrupt context unless | |
2365 | * oops_in_progress is set to 1.. | |
2366 | */ | |
2367 | if (oops_in_progress) { | |
bd8d7cf5 | 2368 | if (down_trylock_console_sem() != 0) |
1da177e4 LT |
2369 | return; |
2370 | } else | |
ac751efa | 2371 | console_lock(); |
1da177e4 LT |
2372 | |
2373 | console_locked = 1; | |
2374 | console_may_schedule = 0; | |
4d091611 | 2375 | for_each_console(c) |
1da177e4 LT |
2376 | if ((c->flags & CON_ENABLED) && c->unblank) |
2377 | c->unblank(); | |
ac751efa | 2378 | console_unlock(); |
1da177e4 | 2379 | } |
1da177e4 | 2380 | |
8d91f8b1 TH |
2381 | /** |
2382 | * console_flush_on_panic - flush console content on panic | |
2383 | * | |
2384 | * Immediately output all pending messages no matter what. | |
2385 | */ | |
2386 | void console_flush_on_panic(void) | |
2387 | { | |
2388 | /* | |
2389 | * If someone else is holding the console lock, trylock will fail | |
2390 | * and may_schedule may be set. Ignore and proceed to unlock so | |
2391 | * that messages are flushed out. As this can be called from any | |
2392 | * context and we don't want to get preempted while flushing, | |
2393 | * ensure may_schedule is cleared. | |
2394 | */ | |
2395 | console_trylock(); | |
2396 | console_may_schedule = 0; | |
2397 | console_unlock(); | |
2398 | } | |
2399 | ||
1da177e4 LT |
2400 | /* |
2401 | * Return the console tty driver structure and its associated index | |
2402 | */ | |
2403 | struct tty_driver *console_device(int *index) | |
2404 | { | |
2405 | struct console *c; | |
2406 | struct tty_driver *driver = NULL; | |
2407 | ||
ac751efa | 2408 | console_lock(); |
4d091611 | 2409 | for_each_console(c) { |
1da177e4 LT |
2410 | if (!c->device) |
2411 | continue; | |
2412 | driver = c->device(c, index); | |
2413 | if (driver) | |
2414 | break; | |
2415 | } | |
ac751efa | 2416 | console_unlock(); |
1da177e4 LT |
2417 | return driver; |
2418 | } | |
2419 | ||
2420 | /* | |
2421 | * Prevent further output on the passed console device so that (for example) | |
2422 | * serial drivers can disable console output before suspending a port, and can | |
2423 | * re-enable output afterwards. | |
2424 | */ | |
2425 | void console_stop(struct console *console) | |
2426 | { | |
ac751efa | 2427 | console_lock(); |
1da177e4 | 2428 | console->flags &= ~CON_ENABLED; |
ac751efa | 2429 | console_unlock(); |
1da177e4 LT |
2430 | } |
2431 | EXPORT_SYMBOL(console_stop); | |
2432 | ||
2433 | void console_start(struct console *console) | |
2434 | { | |
ac751efa | 2435 | console_lock(); |
1da177e4 | 2436 | console->flags |= CON_ENABLED; |
ac751efa | 2437 | console_unlock(); |
1da177e4 LT |
2438 | } |
2439 | EXPORT_SYMBOL(console_start); | |
2440 | ||
7bf69395 FDN |
2441 | static int __read_mostly keep_bootcon; |
2442 | ||
2443 | static int __init keep_bootcon_setup(char *str) | |
2444 | { | |
2445 | keep_bootcon = 1; | |
27083bac | 2446 | pr_info("debug: skip boot console de-registration.\n"); |
7bf69395 FDN |
2447 | |
2448 | return 0; | |
2449 | } | |
2450 | ||
2451 | early_param("keep_bootcon", keep_bootcon_setup); | |
2452 | ||
1da177e4 LT |
2453 | /* |
2454 | * The console driver calls this routine during kernel initialization | |
2455 | * to register the console printing procedure with printk() and to | |
2456 | * print any messages that were printed by the kernel before the | |
2457 | * console driver was initialized. | |
4d091611 RG |
2458 | * |
2459 | * This can happen pretty early during the boot process (because of | |
2460 | * early_printk) - sometimes before setup_arch() completes - be careful | |
2461 | * of what kernel features are used - they may not be initialised yet. | |
2462 | * | |
2463 | * There are two types of consoles - bootconsoles (early_printk) and | |
2464 | * "real" consoles (everything which is not a bootconsole) which are | |
2465 | * handled differently. | |
2466 | * - Any number of bootconsoles can be registered at any time. | |
2467 | * - As soon as a "real" console is registered, all bootconsoles | |
2468 | * will be unregistered automatically. | |
2469 | * - Once a "real" console is registered, any attempt to register a | |
2470 | * bootconsoles will be rejected | |
1da177e4 | 2471 | */ |
4d091611 | 2472 | void register_console(struct console *newcon) |
1da177e4 | 2473 | { |
40dc5651 | 2474 | int i; |
1da177e4 | 2475 | unsigned long flags; |
4d091611 | 2476 | struct console *bcon = NULL; |
23475408 | 2477 | struct console_cmdline *c; |
1da177e4 | 2478 | |
16cf48a6 AB |
2479 | if (console_drivers) |
2480 | for_each_console(bcon) | |
2481 | if (WARN(bcon == newcon, | |
2482 | "console '%s%d' already registered\n", | |
2483 | bcon->name, bcon->index)) | |
2484 | return; | |
2485 | ||
4d091611 RG |
2486 | /* |
2487 | * before we register a new CON_BOOT console, make sure we don't | |
2488 | * already have a valid console | |
2489 | */ | |
2490 | if (console_drivers && newcon->flags & CON_BOOT) { | |
2491 | /* find the last or real console */ | |
2492 | for_each_console(bcon) { | |
2493 | if (!(bcon->flags & CON_BOOT)) { | |
27083bac | 2494 | pr_info("Too late to register bootconsole %s%d\n", |
4d091611 RG |
2495 | newcon->name, newcon->index); |
2496 | return; | |
2497 | } | |
2498 | } | |
69331af7 GH |
2499 | } |
2500 | ||
4d091611 RG |
2501 | if (console_drivers && console_drivers->flags & CON_BOOT) |
2502 | bcon = console_drivers; | |
2503 | ||
2504 | if (preferred_console < 0 || bcon || !console_drivers) | |
1da177e4 LT |
2505 | preferred_console = selected_console; |
2506 | ||
2507 | /* | |
2508 | * See if we want to use this console driver. If we | |
2509 | * didn't select a console we take the first one | |
2510 | * that registers here. | |
2511 | */ | |
2512 | if (preferred_console < 0) { | |
4d091611 RG |
2513 | if (newcon->index < 0) |
2514 | newcon->index = 0; | |
2515 | if (newcon->setup == NULL || | |
2516 | newcon->setup(newcon, NULL) == 0) { | |
2517 | newcon->flags |= CON_ENABLED; | |
2518 | if (newcon->device) { | |
2519 | newcon->flags |= CON_CONSDEV; | |
cd3a1b85 JK |
2520 | preferred_console = 0; |
2521 | } | |
1da177e4 LT |
2522 | } |
2523 | } | |
2524 | ||
2525 | /* | |
2526 | * See if this console matches one we selected on | |
2527 | * the command line. | |
2528 | */ | |
23475408 JP |
2529 | for (i = 0, c = console_cmdline; |
2530 | i < MAX_CMDLINECONSOLES && c->name[0]; | |
2531 | i++, c++) { | |
c7cef0a8 PH |
2532 | if (!newcon->match || |
2533 | newcon->match(newcon, c->name, c->index, c->options) != 0) { | |
2534 | /* default matching */ | |
2535 | BUILD_BUG_ON(sizeof(c->name) != sizeof(newcon->name)); | |
2536 | if (strcmp(c->name, newcon->name) != 0) | |
2537 | continue; | |
2538 | if (newcon->index >= 0 && | |
2539 | newcon->index != c->index) | |
2540 | continue; | |
2541 | if (newcon->index < 0) | |
2542 | newcon->index = c->index; | |
bbeddf52 | 2543 | |
c7cef0a8 PH |
2544 | if (_braille_register_console(newcon, c)) |
2545 | return; | |
2546 | ||
2547 | if (newcon->setup && | |
2548 | newcon->setup(newcon, c->options) != 0) | |
2549 | break; | |
2550 | } | |
bbeddf52 | 2551 | |
4d091611 | 2552 | newcon->flags |= CON_ENABLED; |
ab4af03a | 2553 | if (i == selected_console) { |
4d091611 | 2554 | newcon->flags |= CON_CONSDEV; |
ab4af03a GE |
2555 | preferred_console = selected_console; |
2556 | } | |
1da177e4 LT |
2557 | break; |
2558 | } | |
2559 | ||
4d091611 | 2560 | if (!(newcon->flags & CON_ENABLED)) |
1da177e4 LT |
2561 | return; |
2562 | ||
8259cf43 RG |
2563 | /* |
2564 | * If we have a bootconsole, and are switching to a real console, | |
2565 | * don't print everything out again, since when the boot console, and | |
2566 | * the real console are the same physical device, it's annoying to | |
2567 | * see the beginning boot messages twice | |
2568 | */ | |
2569 | if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV)) | |
4d091611 | 2570 | newcon->flags &= ~CON_PRINTBUFFER; |
1da177e4 LT |
2571 | |
2572 | /* | |
2573 | * Put this console in the list - keep the | |
2574 | * preferred driver at the head of the list. | |
2575 | */ | |
ac751efa | 2576 | console_lock(); |
4d091611 RG |
2577 | if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) { |
2578 | newcon->next = console_drivers; | |
2579 | console_drivers = newcon; | |
2580 | if (newcon->next) | |
2581 | newcon->next->flags &= ~CON_CONSDEV; | |
1da177e4 | 2582 | } else { |
4d091611 RG |
2583 | newcon->next = console_drivers->next; |
2584 | console_drivers->next = newcon; | |
1da177e4 | 2585 | } |
6fe29354 TH |
2586 | |
2587 | if (newcon->flags & CON_EXTENDED) | |
2588 | if (!nr_ext_console_drivers++) | |
2589 | pr_info("printk: continuation disabled due to ext consoles, expect more fragments in /dev/kmsg\n"); | |
2590 | ||
4d091611 | 2591 | if (newcon->flags & CON_PRINTBUFFER) { |
1da177e4 | 2592 | /* |
ac751efa | 2593 | * console_unlock(); will print out the buffered messages |
1da177e4 LT |
2594 | * for us. |
2595 | */ | |
07354eb1 | 2596 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
7ff9554b KS |
2597 | console_seq = syslog_seq; |
2598 | console_idx = syslog_idx; | |
5becfb1d | 2599 | console_prev = syslog_prev; |
07354eb1 | 2600 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
fe3d8ad3 FT |
2601 | /* |
2602 | * We're about to replay the log buffer. Only do this to the | |
2603 | * just-registered console to avoid excessive message spam to | |
2604 | * the already-registered consoles. | |
2605 | */ | |
2606 | exclusive_console = newcon; | |
1da177e4 | 2607 | } |
ac751efa | 2608 | console_unlock(); |
fbc92a34 | 2609 | console_sysfs_notify(); |
8259cf43 RG |
2610 | |
2611 | /* | |
2612 | * By unregistering the bootconsoles after we enable the real console | |
2613 | * we get the "console xxx enabled" message on all the consoles - | |
2614 | * boot consoles, real consoles, etc - this is to ensure that end | |
2615 | * users know there might be something in the kernel's log buffer that | |
2616 | * went to the bootconsole (that they do not see on the real console) | |
2617 | */ | |
27083bac | 2618 | pr_info("%sconsole [%s%d] enabled\n", |
6b802394 KC |
2619 | (newcon->flags & CON_BOOT) ? "boot" : "" , |
2620 | newcon->name, newcon->index); | |
7bf69395 FDN |
2621 | if (bcon && |
2622 | ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV) && | |
2623 | !keep_bootcon) { | |
6b802394 KC |
2624 | /* We need to iterate through all boot consoles, to make |
2625 | * sure we print everything out, before we unregister them. | |
8259cf43 | 2626 | */ |
8259cf43 RG |
2627 | for_each_console(bcon) |
2628 | if (bcon->flags & CON_BOOT) | |
2629 | unregister_console(bcon); | |
8259cf43 | 2630 | } |
1da177e4 LT |
2631 | } |
2632 | EXPORT_SYMBOL(register_console); | |
2633 | ||
40dc5651 | 2634 | int unregister_console(struct console *console) |
1da177e4 | 2635 | { |
40dc5651 | 2636 | struct console *a, *b; |
bbeddf52 | 2637 | int res; |
1da177e4 | 2638 | |
27083bac | 2639 | pr_info("%sconsole [%s%d] disabled\n", |
6b802394 KC |
2640 | (console->flags & CON_BOOT) ? "boot" : "" , |
2641 | console->name, console->index); | |
2642 | ||
bbeddf52 JP |
2643 | res = _braille_unregister_console(console); |
2644 | if (res) | |
2645 | return res; | |
f7511d5f | 2646 | |
bbeddf52 | 2647 | res = 1; |
ac751efa | 2648 | console_lock(); |
1da177e4 LT |
2649 | if (console_drivers == console) { |
2650 | console_drivers=console->next; | |
2651 | res = 0; | |
e9b15b54 | 2652 | } else if (console_drivers) { |
1da177e4 LT |
2653 | for (a=console_drivers->next, b=console_drivers ; |
2654 | a; b=a, a=b->next) { | |
2655 | if (a == console) { | |
2656 | b->next = a->next; | |
2657 | res = 0; | |
2658 | break; | |
40dc5651 | 2659 | } |
1da177e4 LT |
2660 | } |
2661 | } | |
40dc5651 | 2662 | |
6fe29354 TH |
2663 | if (!res && (console->flags & CON_EXTENDED)) |
2664 | nr_ext_console_drivers--; | |
2665 | ||
69331af7 | 2666 | /* |
ab4af03a GE |
2667 | * If this isn't the last console and it has CON_CONSDEV set, we |
2668 | * need to set it on the next preferred console. | |
1da177e4 | 2669 | */ |
69331af7 | 2670 | if (console_drivers != NULL && console->flags & CON_CONSDEV) |
ab4af03a | 2671 | console_drivers->flags |= CON_CONSDEV; |
1da177e4 | 2672 | |
7fa21dd8 | 2673 | console->flags &= ~CON_ENABLED; |
ac751efa | 2674 | console_unlock(); |
fbc92a34 | 2675 | console_sysfs_notify(); |
1da177e4 LT |
2676 | return res; |
2677 | } | |
2678 | EXPORT_SYMBOL(unregister_console); | |
d59745ce | 2679 | |
81cc26f2 TR |
2680 | /* |
2681 | * Some boot consoles access data that is in the init section and which will | |
2682 | * be discarded after the initcalls have been run. To make sure that no code | |
2683 | * will access this data, unregister the boot consoles in a late initcall. | |
2684 | * | |
2685 | * If for some reason, such as deferred probe or the driver being a loadable | |
2686 | * module, the real console hasn't registered yet at this point, there will | |
2687 | * be a brief interval in which no messages are logged to the console, which | |
2688 | * makes it difficult to diagnose problems that occur during this time. | |
2689 | * | |
2690 | * To mitigate this problem somewhat, only unregister consoles whose memory | |
2691 | * intersects with the init section. Note that code exists elsewhere to get | |
2692 | * rid of the boot console as soon as the proper console shows up, so there | |
2693 | * won't be side-effects from postponing the removal. | |
2694 | */ | |
034260d6 | 2695 | static int __init printk_late_init(void) |
0c5564bd | 2696 | { |
4d091611 RG |
2697 | struct console *con; |
2698 | ||
2699 | for_each_console(con) { | |
4c30c6f5 | 2700 | if (!keep_bootcon && con->flags & CON_BOOT) { |
81cc26f2 TR |
2701 | /* |
2702 | * Make sure to unregister boot consoles whose data | |
2703 | * resides in the init section before the init section | |
2704 | * is discarded. Boot consoles whose data will stick | |
2705 | * around will automatically be unregistered when the | |
2706 | * proper console replaces them. | |
2707 | */ | |
2708 | if (init_section_intersects(con, sizeof(*con))) | |
2709 | unregister_console(con); | |
cb00e99c | 2710 | } |
0c5564bd | 2711 | } |
034260d6 | 2712 | hotcpu_notifier(console_cpu_notify, 0); |
0c5564bd RG |
2713 | return 0; |
2714 | } | |
034260d6 | 2715 | late_initcall(printk_late_init); |
0c5564bd | 2716 | |
7ef3d2fd | 2717 | #if defined CONFIG_PRINTK |
dc72c32e FW |
2718 | /* |
2719 | * Delayed printk version, for scheduler-internal messages: | |
2720 | */ | |
dc72c32e | 2721 | #define PRINTK_PENDING_WAKEUP 0x01 |
458df9fd | 2722 | #define PRINTK_PENDING_OUTPUT 0x02 |
dc72c32e FW |
2723 | |
2724 | static DEFINE_PER_CPU(int, printk_pending); | |
dc72c32e FW |
2725 | |
2726 | static void wake_up_klogd_work_func(struct irq_work *irq_work) | |
2727 | { | |
2728 | int pending = __this_cpu_xchg(printk_pending, 0); | |
2729 | ||
458df9fd SR |
2730 | if (pending & PRINTK_PENDING_OUTPUT) { |
2731 | /* If trylock fails, someone else is doing the printing */ | |
2732 | if (console_trylock()) | |
2733 | console_unlock(); | |
dc72c32e FW |
2734 | } |
2735 | ||
2736 | if (pending & PRINTK_PENDING_WAKEUP) | |
2737 | wake_up_interruptible(&log_wait); | |
2738 | } | |
2739 | ||
2740 | static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = { | |
2741 | .func = wake_up_klogd_work_func, | |
2742 | .flags = IRQ_WORK_LAZY, | |
2743 | }; | |
2744 | ||
2745 | void wake_up_klogd(void) | |
2746 | { | |
2747 | preempt_disable(); | |
2748 | if (waitqueue_active(&log_wait)) { | |
2749 | this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP); | |
bb964a92 | 2750 | irq_work_queue(this_cpu_ptr(&wake_up_klogd_work)); |
dc72c32e FW |
2751 | } |
2752 | preempt_enable(); | |
2753 | } | |
717115e1 | 2754 | |
aac74dc4 | 2755 | int printk_deferred(const char *fmt, ...) |
600e1458 | 2756 | { |
600e1458 | 2757 | va_list args; |
600e1458 PZ |
2758 | int r; |
2759 | ||
81954606 | 2760 | preempt_disable(); |
600e1458 | 2761 | va_start(args, fmt); |
a39d4a85 | 2762 | r = vprintk_emit(0, LOGLEVEL_SCHED, NULL, 0, fmt, args); |
600e1458 PZ |
2763 | va_end(args); |
2764 | ||
458df9fd | 2765 | __this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT); |
bb964a92 | 2766 | irq_work_queue(this_cpu_ptr(&wake_up_klogd_work)); |
81954606 | 2767 | preempt_enable(); |
600e1458 PZ |
2768 | |
2769 | return r; | |
2770 | } | |
2771 | ||
1da177e4 LT |
2772 | /* |
2773 | * printk rate limiting, lifted from the networking subsystem. | |
2774 | * | |
641de9d8 UKK |
2775 | * This enforces a rate limit: not more than 10 kernel messages |
2776 | * every 5s to make a denial-of-service attack impossible. | |
1da177e4 | 2777 | */ |
641de9d8 UKK |
2778 | DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10); |
2779 | ||
5c828713 | 2780 | int __printk_ratelimit(const char *func) |
1da177e4 | 2781 | { |
5c828713 | 2782 | return ___ratelimit(&printk_ratelimit_state, func); |
1da177e4 | 2783 | } |
5c828713 | 2784 | EXPORT_SYMBOL(__printk_ratelimit); |
f46c4833 AM |
2785 | |
2786 | /** | |
2787 | * printk_timed_ratelimit - caller-controlled printk ratelimiting | |
2788 | * @caller_jiffies: pointer to caller's state | |
2789 | * @interval_msecs: minimum interval between prints | |
2790 | * | |
2791 | * printk_timed_ratelimit() returns true if more than @interval_msecs | |
2792 | * milliseconds have elapsed since the last time printk_timed_ratelimit() | |
2793 | * returned true. | |
2794 | */ | |
2795 | bool printk_timed_ratelimit(unsigned long *caller_jiffies, | |
2796 | unsigned int interval_msecs) | |
2797 | { | |
249771b8 AE |
2798 | unsigned long elapsed = jiffies - *caller_jiffies; |
2799 | ||
2800 | if (*caller_jiffies && elapsed <= msecs_to_jiffies(interval_msecs)) | |
2801 | return false; | |
2802 | ||
2803 | *caller_jiffies = jiffies; | |
2804 | return true; | |
f46c4833 AM |
2805 | } |
2806 | EXPORT_SYMBOL(printk_timed_ratelimit); | |
456b565c SK |
2807 | |
2808 | static DEFINE_SPINLOCK(dump_list_lock); | |
2809 | static LIST_HEAD(dump_list); | |
2810 | ||
2811 | /** | |
2812 | * kmsg_dump_register - register a kernel log dumper. | |
6485536b | 2813 | * @dumper: pointer to the kmsg_dumper structure |
456b565c SK |
2814 | * |
2815 | * Adds a kernel log dumper to the system. The dump callback in the | |
2816 | * structure will be called when the kernel oopses or panics and must be | |
2817 | * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise. | |
2818 | */ | |
2819 | int kmsg_dump_register(struct kmsg_dumper *dumper) | |
2820 | { | |
2821 | unsigned long flags; | |
2822 | int err = -EBUSY; | |
2823 | ||
2824 | /* The dump callback needs to be set */ | |
2825 | if (!dumper->dump) | |
2826 | return -EINVAL; | |
2827 | ||
2828 | spin_lock_irqsave(&dump_list_lock, flags); | |
2829 | /* Don't allow registering multiple times */ | |
2830 | if (!dumper->registered) { | |
2831 | dumper->registered = 1; | |
fb842b00 | 2832 | list_add_tail_rcu(&dumper->list, &dump_list); |
456b565c SK |
2833 | err = 0; |
2834 | } | |
2835 | spin_unlock_irqrestore(&dump_list_lock, flags); | |
2836 | ||
2837 | return err; | |
2838 | } | |
2839 | EXPORT_SYMBOL_GPL(kmsg_dump_register); | |
2840 | ||
2841 | /** | |
2842 | * kmsg_dump_unregister - unregister a kmsg dumper. | |
6485536b | 2843 | * @dumper: pointer to the kmsg_dumper structure |
456b565c SK |
2844 | * |
2845 | * Removes a dump device from the system. Returns zero on success and | |
2846 | * %-EINVAL otherwise. | |
2847 | */ | |
2848 | int kmsg_dump_unregister(struct kmsg_dumper *dumper) | |
2849 | { | |
2850 | unsigned long flags; | |
2851 | int err = -EINVAL; | |
2852 | ||
2853 | spin_lock_irqsave(&dump_list_lock, flags); | |
2854 | if (dumper->registered) { | |
2855 | dumper->registered = 0; | |
fb842b00 | 2856 | list_del_rcu(&dumper->list); |
456b565c SK |
2857 | err = 0; |
2858 | } | |
2859 | spin_unlock_irqrestore(&dump_list_lock, flags); | |
fb842b00 | 2860 | synchronize_rcu(); |
456b565c SK |
2861 | |
2862 | return err; | |
2863 | } | |
2864 | EXPORT_SYMBOL_GPL(kmsg_dump_unregister); | |
2865 | ||
7ff9554b KS |
2866 | static bool always_kmsg_dump; |
2867 | module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR); | |
2868 | ||
456b565c SK |
2869 | /** |
2870 | * kmsg_dump - dump kernel log to kernel message dumpers. | |
2871 | * @reason: the reason (oops, panic etc) for dumping | |
2872 | * | |
e2ae715d KS |
2873 | * Call each of the registered dumper's dump() callback, which can |
2874 | * retrieve the kmsg records with kmsg_dump_get_line() or | |
2875 | * kmsg_dump_get_buffer(). | |
456b565c SK |
2876 | */ |
2877 | void kmsg_dump(enum kmsg_dump_reason reason) | |
2878 | { | |
456b565c | 2879 | struct kmsg_dumper *dumper; |
456b565c SK |
2880 | unsigned long flags; |
2881 | ||
c22ab332 MG |
2882 | if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump) |
2883 | return; | |
2884 | ||
e2ae715d KS |
2885 | rcu_read_lock(); |
2886 | list_for_each_entry_rcu(dumper, &dump_list, list) { | |
2887 | if (dumper->max_reason && reason > dumper->max_reason) | |
2888 | continue; | |
2889 | ||
2890 | /* initialize iterator with data about the stored records */ | |
2891 | dumper->active = true; | |
2892 | ||
2893 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2894 | dumper->cur_seq = clear_seq; | |
2895 | dumper->cur_idx = clear_idx; | |
2896 | dumper->next_seq = log_next_seq; | |
2897 | dumper->next_idx = log_next_idx; | |
2898 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2899 | ||
2900 | /* invoke dumper which will iterate over records */ | |
2901 | dumper->dump(dumper, reason); | |
2902 | ||
2903 | /* reset iterator */ | |
2904 | dumper->active = false; | |
2905 | } | |
2906 | rcu_read_unlock(); | |
2907 | } | |
2908 | ||
2909 | /** | |
533827c9 | 2910 | * kmsg_dump_get_line_nolock - retrieve one kmsg log line (unlocked version) |
e2ae715d KS |
2911 | * @dumper: registered kmsg dumper |
2912 | * @syslog: include the "<4>" prefixes | |
2913 | * @line: buffer to copy the line to | |
2914 | * @size: maximum size of the buffer | |
2915 | * @len: length of line placed into buffer | |
2916 | * | |
2917 | * Start at the beginning of the kmsg buffer, with the oldest kmsg | |
2918 | * record, and copy one record into the provided buffer. | |
2919 | * | |
2920 | * Consecutive calls will return the next available record moving | |
2921 | * towards the end of the buffer with the youngest messages. | |
2922 | * | |
2923 | * A return value of FALSE indicates that there are no more records to | |
2924 | * read. | |
533827c9 AV |
2925 | * |
2926 | * The function is similar to kmsg_dump_get_line(), but grabs no locks. | |
e2ae715d | 2927 | */ |
533827c9 AV |
2928 | bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog, |
2929 | char *line, size_t size, size_t *len) | |
e2ae715d | 2930 | { |
62e32ac3 | 2931 | struct printk_log *msg; |
e2ae715d KS |
2932 | size_t l = 0; |
2933 | bool ret = false; | |
2934 | ||
2935 | if (!dumper->active) | |
2936 | goto out; | |
7ff9554b | 2937 | |
e2ae715d KS |
2938 | if (dumper->cur_seq < log_first_seq) { |
2939 | /* messages are gone, move to first available one */ | |
2940 | dumper->cur_seq = log_first_seq; | |
2941 | dumper->cur_idx = log_first_idx; | |
2942 | } | |
456b565c | 2943 | |
e2ae715d | 2944 | /* last entry */ |
533827c9 | 2945 | if (dumper->cur_seq >= log_next_seq) |
e2ae715d | 2946 | goto out; |
456b565c | 2947 | |
e2ae715d | 2948 | msg = log_from_idx(dumper->cur_idx); |
5becfb1d | 2949 | l = msg_print_text(msg, 0, syslog, line, size); |
e2ae715d KS |
2950 | |
2951 | dumper->cur_idx = log_next(dumper->cur_idx); | |
2952 | dumper->cur_seq++; | |
2953 | ret = true; | |
e2ae715d KS |
2954 | out: |
2955 | if (len) | |
2956 | *len = l; | |
2957 | return ret; | |
2958 | } | |
533827c9 AV |
2959 | |
2960 | /** | |
2961 | * kmsg_dump_get_line - retrieve one kmsg log line | |
2962 | * @dumper: registered kmsg dumper | |
2963 | * @syslog: include the "<4>" prefixes | |
2964 | * @line: buffer to copy the line to | |
2965 | * @size: maximum size of the buffer | |
2966 | * @len: length of line placed into buffer | |
2967 | * | |
2968 | * Start at the beginning of the kmsg buffer, with the oldest kmsg | |
2969 | * record, and copy one record into the provided buffer. | |
2970 | * | |
2971 | * Consecutive calls will return the next available record moving | |
2972 | * towards the end of the buffer with the youngest messages. | |
2973 | * | |
2974 | * A return value of FALSE indicates that there are no more records to | |
2975 | * read. | |
2976 | */ | |
2977 | bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog, | |
2978 | char *line, size_t size, size_t *len) | |
2979 | { | |
2980 | unsigned long flags; | |
2981 | bool ret; | |
2982 | ||
2983 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2984 | ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len); | |
2985 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2986 | ||
2987 | return ret; | |
2988 | } | |
e2ae715d KS |
2989 | EXPORT_SYMBOL_GPL(kmsg_dump_get_line); |
2990 | ||
2991 | /** | |
2992 | * kmsg_dump_get_buffer - copy kmsg log lines | |
2993 | * @dumper: registered kmsg dumper | |
2994 | * @syslog: include the "<4>" prefixes | |
4f0f4af5 | 2995 | * @buf: buffer to copy the line to |
e2ae715d KS |
2996 | * @size: maximum size of the buffer |
2997 | * @len: length of line placed into buffer | |
2998 | * | |
2999 | * Start at the end of the kmsg buffer and fill the provided buffer | |
3000 | * with as many of the the *youngest* kmsg records that fit into it. | |
3001 | * If the buffer is large enough, all available kmsg records will be | |
3002 | * copied with a single call. | |
3003 | * | |
3004 | * Consecutive calls will fill the buffer with the next block of | |
3005 | * available older records, not including the earlier retrieved ones. | |
3006 | * | |
3007 | * A return value of FALSE indicates that there are no more records to | |
3008 | * read. | |
3009 | */ | |
3010 | bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, | |
3011 | char *buf, size_t size, size_t *len) | |
3012 | { | |
3013 | unsigned long flags; | |
3014 | u64 seq; | |
3015 | u32 idx; | |
3016 | u64 next_seq; | |
3017 | u32 next_idx; | |
5becfb1d | 3018 | enum log_flags prev; |
e2ae715d KS |
3019 | size_t l = 0; |
3020 | bool ret = false; | |
3021 | ||
3022 | if (!dumper->active) | |
3023 | goto out; | |
3024 | ||
3025 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
3026 | if (dumper->cur_seq < log_first_seq) { | |
3027 | /* messages are gone, move to first available one */ | |
3028 | dumper->cur_seq = log_first_seq; | |
3029 | dumper->cur_idx = log_first_idx; | |
3030 | } | |
3031 | ||
3032 | /* last entry */ | |
3033 | if (dumper->cur_seq >= dumper->next_seq) { | |
3034 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
3035 | goto out; | |
3036 | } | |
3037 | ||
3038 | /* calculate length of entire buffer */ | |
3039 | seq = dumper->cur_seq; | |
3040 | idx = dumper->cur_idx; | |
5becfb1d | 3041 | prev = 0; |
e2ae715d | 3042 | while (seq < dumper->next_seq) { |
62e32ac3 | 3043 | struct printk_log *msg = log_from_idx(idx); |
e2ae715d | 3044 | |
5becfb1d | 3045 | l += msg_print_text(msg, prev, true, NULL, 0); |
e2ae715d KS |
3046 | idx = log_next(idx); |
3047 | seq++; | |
5becfb1d | 3048 | prev = msg->flags; |
e2ae715d KS |
3049 | } |
3050 | ||
3051 | /* move first record forward until length fits into the buffer */ | |
3052 | seq = dumper->cur_seq; | |
3053 | idx = dumper->cur_idx; | |
5becfb1d | 3054 | prev = 0; |
e2ae715d | 3055 | while (l > size && seq < dumper->next_seq) { |
62e32ac3 | 3056 | struct printk_log *msg = log_from_idx(idx); |
456b565c | 3057 | |
5becfb1d | 3058 | l -= msg_print_text(msg, prev, true, NULL, 0); |
e2ae715d KS |
3059 | idx = log_next(idx); |
3060 | seq++; | |
5becfb1d | 3061 | prev = msg->flags; |
456b565c | 3062 | } |
e2ae715d KS |
3063 | |
3064 | /* last message in next interation */ | |
3065 | next_seq = seq; | |
3066 | next_idx = idx; | |
3067 | ||
3068 | l = 0; | |
3069 | while (seq < dumper->next_seq) { | |
62e32ac3 | 3070 | struct printk_log *msg = log_from_idx(idx); |
e2ae715d | 3071 | |
5becfb1d | 3072 | l += msg_print_text(msg, prev, syslog, buf + l, size - l); |
e2ae715d KS |
3073 | idx = log_next(idx); |
3074 | seq++; | |
5becfb1d | 3075 | prev = msg->flags; |
e2ae715d KS |
3076 | } |
3077 | ||
3078 | dumper->next_seq = next_seq; | |
3079 | dumper->next_idx = next_idx; | |
3080 | ret = true; | |
7ff9554b | 3081 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
e2ae715d KS |
3082 | out: |
3083 | if (len) | |
3084 | *len = l; | |
3085 | return ret; | |
3086 | } | |
3087 | EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer); | |
456b565c | 3088 | |
533827c9 AV |
3089 | /** |
3090 | * kmsg_dump_rewind_nolock - reset the interator (unlocked version) | |
3091 | * @dumper: registered kmsg dumper | |
3092 | * | |
3093 | * Reset the dumper's iterator so that kmsg_dump_get_line() and | |
3094 | * kmsg_dump_get_buffer() can be called again and used multiple | |
3095 | * times within the same dumper.dump() callback. | |
3096 | * | |
3097 | * The function is similar to kmsg_dump_rewind(), but grabs no locks. | |
3098 | */ | |
3099 | void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper) | |
3100 | { | |
3101 | dumper->cur_seq = clear_seq; | |
3102 | dumper->cur_idx = clear_idx; | |
3103 | dumper->next_seq = log_next_seq; | |
3104 | dumper->next_idx = log_next_idx; | |
3105 | } | |
3106 | ||
e2ae715d KS |
3107 | /** |
3108 | * kmsg_dump_rewind - reset the interator | |
3109 | * @dumper: registered kmsg dumper | |
3110 | * | |
3111 | * Reset the dumper's iterator so that kmsg_dump_get_line() and | |
3112 | * kmsg_dump_get_buffer() can be called again and used multiple | |
3113 | * times within the same dumper.dump() callback. | |
3114 | */ | |
3115 | void kmsg_dump_rewind(struct kmsg_dumper *dumper) | |
3116 | { | |
3117 | unsigned long flags; | |
3118 | ||
3119 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
533827c9 | 3120 | kmsg_dump_rewind_nolock(dumper); |
e2ae715d | 3121 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
456b565c | 3122 | } |
e2ae715d | 3123 | EXPORT_SYMBOL_GPL(kmsg_dump_rewind); |
196779b9 | 3124 | |
98e5e1bf TH |
3125 | static char dump_stack_arch_desc_str[128]; |
3126 | ||
3127 | /** | |
3128 | * dump_stack_set_arch_desc - set arch-specific str to show with task dumps | |
3129 | * @fmt: printf-style format string | |
3130 | * @...: arguments for the format string | |
3131 | * | |
3132 | * The configured string will be printed right after utsname during task | |
3133 | * dumps. Usually used to add arch-specific system identifiers. If an | |
3134 | * arch wants to make use of such an ID string, it should initialize this | |
3135 | * as soon as possible during boot. | |
3136 | */ | |
3137 | void __init dump_stack_set_arch_desc(const char *fmt, ...) | |
3138 | { | |
3139 | va_list args; | |
3140 | ||
3141 | va_start(args, fmt); | |
3142 | vsnprintf(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str), | |
3143 | fmt, args); | |
3144 | va_end(args); | |
3145 | } | |
3146 | ||
196779b9 TH |
3147 | /** |
3148 | * dump_stack_print_info - print generic debug info for dump_stack() | |
3149 | * @log_lvl: log level | |
3150 | * | |
3151 | * Arch-specific dump_stack() implementations can use this function to | |
3152 | * print out the same debug information as the generic dump_stack(). | |
3153 | */ | |
3154 | void dump_stack_print_info(const char *log_lvl) | |
3155 | { | |
3156 | printk("%sCPU: %d PID: %d Comm: %.20s %s %s %.*s\n", | |
3157 | log_lvl, raw_smp_processor_id(), current->pid, current->comm, | |
3158 | print_tainted(), init_utsname()->release, | |
3159 | (int)strcspn(init_utsname()->version, " "), | |
3160 | init_utsname()->version); | |
98e5e1bf TH |
3161 | |
3162 | if (dump_stack_arch_desc_str[0] != '\0') | |
3163 | printk("%sHardware name: %s\n", | |
3164 | log_lvl, dump_stack_arch_desc_str); | |
3d1cb205 TH |
3165 | |
3166 | print_worker_info(log_lvl, current); | |
196779b9 TH |
3167 | } |
3168 | ||
a43cb95d TH |
3169 | /** |
3170 | * show_regs_print_info - print generic debug info for show_regs() | |
3171 | * @log_lvl: log level | |
3172 | * | |
3173 | * show_regs() implementations can use this function to print out generic | |
3174 | * debug information. | |
3175 | */ | |
3176 | void show_regs_print_info(const char *log_lvl) | |
3177 | { | |
3178 | dump_stack_print_info(log_lvl); | |
3179 | ||
3180 | printk("%stask: %p ti: %p task.ti: %p\n", | |
3181 | log_lvl, current, current_thread_info(), | |
3182 | task_thread_info(current)); | |
3183 | } | |
3184 | ||
7ef3d2fd | 3185 | #endif |